Introduction
The COVID-19 global pandemic was first reported in Wuhan, China, followed by subsequent
outbreaks in other parts of Asia, Western Europe, and North America (Miller et al.
2020; Velavan and Meyer 2020). Towards the end of February 2020, the first case of
COVID-19 was reported in Brazil, marking the arrival of the COVID-19 wave in South
America (Miller et al. 2020). Recently, the COVID-19 wave has hit Africa, turning
the continent into the next potential hotspot for the global pandemic. To date, significant
outbreaks have been reported in all regions of Africa, including East Africa, West
Africa, southern Africa, central Africa, and North Africa (Africa CDC 2020; Martinez-Alvarez
et al. 2020). As of 6 August 2020, 1,007,366 confirmed cases of COVID-19 and 22,066
deaths have been reported in Africa, and the infections continue to rise rapidly (Africa
CDC 2020). Southern Africa, with a total of 565,100 confirmed cases, accounts for
slightly more than half (i.e., 56%) of the cases in Africa. The World Health Organization
predicts that up to 190,000 could die in Africa if COVID-19 is not controlled (WHO
2020c, d).
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the etiologic agent
that causes COVID-19, is transmitted predominantly via respiratory droplets released
by symptomatic and asymptomatic infected persons via coughing, sneezing, and through
direct contact with contaminated surfaces (WHO 2020b, c). Accordingly, current control
methods for minimizing transmission via these routes include wearing appropriate personal
protective equipment (PPE), practicing hand hygiene via frequent and regular hand
washing, and social distancing based on national lockdowns and quarantines (WHO 2020b,
c). Several recent studies have suggested the fecal–oral route as a potential transmission
mode (Goh et al. 2020, Gu et al. 2020; Gwenzi 2020b; Heller et al. 2020; Hindson 2020).
For example, the fecal–oral route transmission was discussed in detail in an earlier
review paper focusing on low-income countries (Gwenzi 2020b). This is because SARS-CoV-2
RNA has been detected in the human gastrointestinal tract, stools, and even raw wastewater
(Ahmed et al. 2020; Lodder and de Roda Husman 2020; Randazzo et al. 2020; Yeo et al.
2020).
The outbreak of COVID-19 in Africa, particularly in sub-Saharan Africa, is significant
in a number of respects. First, the region experiences chronic poverty, and has poor
social security and health care systems with limited capacity to cope with a pandemic
of such magnitude. Second, the COVID-wave arrived during wintertime, when conditions
are conducive for the transmission and persistence of SARS-CoV-2. Finally, the region
experiences a variety of inherent risk factors predisposing humans to COVID-19. Hence,
novel COVID-19 transmission modes via fecal contamination of drinking water and food
sources, and human exposure via the fecal-oral route cannot be ruled out. However,
an African perspective on the practical implications of the potential for novel transmission
of COVID-19 and its potential interactions with the inherent socioeconomic drivers,
risk factors, and challenges in Africa is still lacking. This perspective, which targets
policy-makers, practitioners, aid agencies, and the research community, seeks to address
this gap. Figure 1 summarizes the focus of the current perspective.
Fig. 1
A summary of the COVID-19 characteristics and socioeconomic drivers, risk factors,
challenges, and proposed additional safeguards in Africa
The current perspective posits that, collectively, these socioeconomic drivers, risk
factors, and challenges, coupled with the highly infectious COVID-19 with a fatality
rate of about 4% and a high risk for novel transmission, constitute “dangerous liaisons.”
In turn, this will result in adverse human health outcomes and long-lasting knock-on
effects in fragile African countries. Hence, novel transmission dynamics and further
safeguards should be considered and integrated into the current COVID-19 control measures.
The purpose of this perspective is to draw the attention of the public, policy-makers,
practitioners, and the research community to issues currently overlooked in the discussion
on COVID-19 in Africa. First, novel transmission modes and their lines of supporting
evidence are presented. The socioeconomic drivers, risk factors, and challenges predisposing
humans in Africa to COVID-19 are discussed. Finally, the need to consider novel transmission
dynamics and the corresponding additional safeguards is highlighted.
Notably, this perspective does not intend to downplay the critical role of COVID-19
transmission via the respiratory and direct contact routes and the associated mitigation
methods based on hand hygiene, use of PPE, and social distancing. Instead, the current
study presents a perspective on COVID-19 transmission dynamics and control methods
in the African context, an aspect which is currently missing in the existing COVID-19
literature. Given that COVID-19 has now hit Africa, any perspectives on the topic
are best shared in a timely and rapid manner, hence the current study.
COVID-19: risk factors, drivers, and challenges
Socioeconomic drivers
Africa has markedly low economic development, evidenced by chronic poverty, unemployment,
and a critical shortage of essential goods and services (Buheji et al. 2020; Mahler
et al. 2020). Because of these shortages of goods and services, people literally queue
for nearly everything (Jones 2019). This includes water, sanitation facilities, financial
services (e.g., banking), public transport, shopping, and payment of utility bills,
as well as personal registration and travel documents such as birth and death certificates,
and passports. While some of these services are provided via online platforms in developed
regions, such systems are either non-existent or unreliable in Africa. This results
in overcrowding, making it difficult to consistently maintain social distancing.
Because of the low economic development in several African countries, there is a high
flux of people among neighboring countries in search of employment opportunities,
goods, and services (Moyo and Nshimbi 2020). Poor border control systems and highly
porous national borders mean that illegal cross-border travel and human trafficking
via undesignated entry points and subsequent deportations are common (Adepoju 2005;
Truong 2005). Poor urban planning has led to informal settlements such as overcrowded
slums and squatter camps (Durand-Lasserve 2006), while political instability and humanitarian
disasters have forced people into refugee camps (McNatt 2020). Unemployment is very
high; thus the bulk of the population relies on informal jobs such as vending and
manual jobs for income and livelihood. With low income and poor social security systems,
COVID-19 control measures such as self-quarantine, social distancing, and use of PPE
present significant challenges in Africa.
Literacy levels in Africa are low, which accounts for a number of misconceptions,
myths, and poor understanding of the health risks posed by COVID-19 (Abuya et al.
2020; Chersich et al. 2020; Nachega et al. 2020a). Anecdotal evidence suggests that
several perceptions, myths, and attitudes exist in some African countries. For example,
some believe that native Black Africans are genetically resistant to COVID-19. Hence,
COVID-19 is perceived to affect people of specific racial descent and regions who
are genetically predisposed to the disease. These myths and misconceptions may be
attributed to the fact that significant outbreaks in Africa have generally lagged
behind those in Asia, Europe, and South America (Miller et al. 2020; Nachega et al.
2020b). Such myths and misconception have no scientific basis, but may promote the
transmission of COVID-19 and even delay implementation of control measures. Moreover,
a lack of trust in public institutions and governance systems raises concerns about
whether the public will strictly comply with government-imposed restrictions and mitigation
measures (Costa 2020; Khemani 2020). Collectively, these socioeconomic factors have
potential impacts on the COVID-19 transmission dynamics and effectiveness of control
methods.
Challenges
Poor water, wastewater, and sanitation infrastructure
A significant portion of the African population still lacks access to clean drinking water,
wastewater treatment systems, and proper solid waste and sanitary facilities such
as modern toilets (Fuente et al. 2020; Momberg et al. 2020). Hence, raw and partially
treated wastewater from municipal sewer systems, health care facilities, on-site sanitation
systems, and even funeral homes are directly discharged into surface and groundwater
systems without prior treatment (Gwenzi 2020a, c). Lacking sanitary landfills and
incinerators, hazardous solid wastes, including municipal wastes, and infectious materials
from health care systems (Ali et al. 2017) and the funeral industry such as used PPE,
dressings, and bandages are often co-mixed and disposed of in non-engineered waste
dumps (Patwary et al. 2011). These practices increase the risk of COVID-19 transmission
and drinking water contamination with SARS-CoV-2 and other human pathogens.
Because of lack of proper sanitation facilities, unimproved rudimentary methods such
as pit latrines, poorly designed septic tanks, and open defecation are still common
(Yiougo et al. 2011; Okullo et al. 2017). The World Health Organization (WHO) recommends
the following with respect to the siting of on-site sanitation systems relative to
drinking water sources: (1) a depth difference of at least 1.5 m between the groundwater
table and the base of the on-site sanitation system, with larger values recommended
for areas with highly porous sandy and gravelly substrate with higher hydraulic conductivity,
and (2) a horizontal distance of at least 30 m between drinking water sources and
on-site sanitation systems (Tilley et al. 2014; WHO 2020e). However, such recommendations
are often not achievable in African settings, because the landholding per household
is frequently too small to allow such physical distances. Hence, in reality, on-site
sanitation systems are often closely juxtaposed with community water sources such
as wetlands, wells, and boreholes (Beukes et al. 2017; Potgieter et al. 2020). Yet
the bulk of the population in Africa lacking access to treated clean drinking water
relies on untreated water from unprotected sources such as shallow hand-dug wells,
rivers, and boreholes (Nguyen et al. 2014). Thus, the potential for fecal–oral route
transmission of pathogens including SARS-CoV-2 could be higher than initially perceived.
The recurrent outbreaks of waterborne diseases such as cholera and typhoid in several
African countries support this notion (Gwenzi and Sanganyado 2019).
In some settings such as informal settlements, both water and on-site sanitation systems
are shared by several households (Siminyu et al. 2017; Caruso and Freeman 2020). This
causes overcrowding and increases the risk of community transmission of COVID-19.
Overcrowding at such shared water and sanitation points makes social-distancing problematic.
In densely populated settlements, community shared sanitation facilities are prone
to overloading, which may in turn result in overflowing and spillage into drinking
water sources. A recent review by Caruso and Freeman (2020) discussed the risks of
COVID-19 transmission via shared sanitation facilities. In such facilities, SARS-CoV-2
transmission may occur via the following pathways: (1) airborne route through aerosolization
of toilet wastewater or effluent during flushing, and (2) direct contact with contaminated
surfaces, also known as fomites (Caruso and Freeman 2020). Surprisingly, the recent
WHO (2020e) update on COVID-19 focusing on water, sanitation, and hygiene is silent
on the several issues highlighted here, and the risks of COVID-19 transmission associated
with shared water and sanitation facilities. This highlights the need to re-contextualize
and adapt generic control measures to the African socioeconomic settings, cultures,
and norms.
Weak and poorly enforced food hygiene, safety, and quality standards
Food hygiene, quality, and safety standards are often non-existent or weak and poorly
enforced in Africa (Boatemaa et al. 2019; Madaki and Bavorova 2019). Thus, unhygienic
practices such as the use of bare hands, sneezing, blowing of one’s nostrils, coughing,
and spitting by infected persons during food processing, packaging, and serving may
occur. These practices may lead to food cross-contamination with SARS-CoV-2. Comprehensive
COVID-19 testing of workers in the food industry in Africa using polymerase chain
reaction (PCR) test kits is time-consuming and expensive. The extent to which COVID-19
testing is conducted among workers in the food industry in most African countries
is also unknown. Informal food vending in open food markets, streets, and even public
transport such as buses and commuter omnibuses is common in Africa (Songe et al. 2017).
Although no data exist showing COVID-19 contamination via such vended foods, vector-mediated
contamination of food from open and street markets has been reported in some African
countries (Phoku et al. 2016; Songe et al. 2017). Such practices increase the risk
of food contamination with SARS-CoV-2 via direct contact with infected surfaces, cross-contamination,
and vectors such as houseflies. This is because such open and street food markets
have no proper sanitation and hand-washing facilities. Even in cases where shared
public sanitation and hand-washing facilities exist, these facilities often lack sanitizers
and soap required for effective disinfection.
In Africa, as in parts of Asia, several wild animals including ungulates, rodents,
and birds are consumed as food in some communities (Fitzhenry et al. 2019; Martins
and Shackleton 2019). The health risks posed by the consumption of wild animal products
during COVID-19 outbreaks are still poorly understood. However, the transfer of zoonotic
diseases from wild animals to livestock and then humans is well-documented (Mohamed
2020; Sichewo et al. 2020). To date, no studies exist investigating whether or not
wild food animals in Africa are potential hosts of SARS-CoV-2. However, some studies
suggest that SARS-CoV-1, the etiologic agent causing SARS-1, was detected in palm
civet food products (Ahmadiara 2020). Existing studies assessing the risks of COVID-19
transmission via food (e.g., Oakenfull and Wilson 2020) do not consider the exposure
risks associated with the consumption of wild animal products such as bush-meat. This
points to the need for caution in regions where consumption of wild food products
is common. As a precaution, it is advisable to avoid consuming wild animal products
during a COVID-19 outbreak. In cases where the consumption of such wild animal foods
is unavoidable, precautions must be taken (e.g., proper cooking).
Unhygienic funeral practices
Detailed guidelines and step-by-step procedures exist for the management and disposal
of the remains of patients who have died from COVID-19 (Finegan et al. 2020, WHO 2020a).
WHO (2020a) recommendations include the following, among others: (1) people preparing
the body should not kiss the deceased, and should thoroughly wash hands with soap
and water afterwards; (2) during body viewing, family members and friends should not
touch or kiss the deceased, and physical distancing should be strictly applied; and
(3) people with respiratory problems should not participate in body viewing or should
at least wear a medical mask. Although these guidelines are comprehensive, their implementation
presents several challenges, especially among poor communities. First, the recommendations
assume that most of the COVID-19 deaths are diagnosed. However, due to poor health
care coverage and low rates of COVID-19 testing in Africa, a significant number of
deaths are likely to occur at home in remote rural areas without any COVID-19 diagnosis.
Thus, it will be difficult to differentiate deaths due to COVID-19 from those attributable
to other diseases. It is also unclear whether these recommendations have been widely
disseminated at the country level, including remote rural areas. In most African countries,
the living are closely linked to the dead through strong cultural and religious beliefs.
Hence, regardless of one’s health status and the cause of death, some burial and funeral
rituals such as body viewing, kissing, and touching are common. Medical masks, laundry
detergents, and chemical disinfectants such as chlorine cited in the WHO (2020a) recommendations
are rarely affordable and available in typical rural settings in Africa. As mass fatalities
due to COVID-19 occur, such elaborate procedures may be considered cumbersome. Instead,
several risky practices, including burials within homesteads and in areas with shallow
groundwater systems and even in wetlands, are likely to occur, thus increasing the
risk of pollution of drinking water sources (Zume 2011). In summary, existing guidelines
appear to have been developed for middle- to high-income communities, but are unlikely
to be feasible among low-income and vulnerable communities in Africa, some of which
cannot even afford basic food. In some countries, where PPE is now mandatory, the
sharing of masks among the poor has been reported in an effort to avoid arrest. Hence,
for such recommendations to be feasible, these material requirements should be provided
either by government or aid agencies as part of COVID-19 control measures. Yet most
African governments lack the resources and capacity to supply adequate PPE even to
health care professionals.
Weak and under-funded health care and social security systems
Weak and poorly funded health care and social security systems in Africa cannot cope
with widespread outbreaks of infections such as COVID-19 (Ji et al. 2020). The lack
of coping capacity in Africa is even evident in other diseases such as cholera and
typhoid (Ahmed et al. 2011). The presence of weak social security systems coupled
with low formal employment implies that mandatory social distancing via national lockdowns
and self-quarantine significantly threaten household income, livelihoods, and food
security of vulnerable communities. This may result in long-term adverse effects which
may limit post-COVID-19 recovery.
Public medical diagnostic laboratories remain few and poorly equipped. Thus, Africa
is currently experiencing a critical shortage of reverse transcriptase quantitative
PCR (RT-qPCR) testing kits required for reliable detection of SARS-CoV-2, as such
kits are expensive, and hence only a limited quantity exists in Africa (Shereen et
al. 2020). Currently, most COVID-19 testing centers are confined to major urban centers,
while such facilities are lacking in remote rural areas, where a significant proportion
of the African population lives. Lacking PCR kits, defective and less reliable test
kits have been used, often resulting in misleading results. African countries also
lack reliable COVID-19 data on the number of people tested, confirmed cases, deaths,
and recoveries. Thus, the extent and severity of COVID-19 transmission in most African
countries is not known with certainty. Yet such data are critical for policy formulation,
targeting the allocation of scarce resources, and even determining whether to upgrade
or downgrade control measures such as national lockdowns.
Human disease and public health surveillance systems are often weak and even missing
in most African countries (Tambo et al. 2014; Siedner et al. 2015). Yet such systems
are critical for the early detection and control of infectious diseases including
COVID-19. Lacking such surveillance systems, emergency response systems tend to be
slow and poorly coordinated, thereby promoting rapid transmission of infectious diseases
such as COVID-19. Due to the lack of resources and expertise, most African countries
typically rely on donations from developed countries and the international community.
Thus, any delays or lack of such donor or international support will delay implementation
of control measures, allowing COVID-19 transmission to further expand.
Given the challenges highlighted, Africa, and particularly sub-Saharan Africa, has
a high burden of human diseases including immune-suppressing HIV/AIDS, tuberculosis,
malaria, Chikungunya virus, Ebola virus, and even waterborne diseases (e.g., cholera,
typhoid) (Confraria and Wang 2020). Human disease vectors and pathogens proliferate
and persist under the tropical conditions predominant in sub-Saharan Africa (Barclay
2008). Co-infections may synergistically interact with COVID-19, and predispose humans
to adverse health risks and outcomes (Bengoechea and Bamford 2020; Lin et al. 2020).
Therefore, in light of the high disease burden, synergistic interactions between COVID-19
and co-infections are expected to be more pronounced in Africa than in developing
countries.
Climatic and weather drivers of COVID-19 transmission
Evidence shows that COVID-19 transmission dynamics are often correlated or coupled
with climatic and weather drivers, with cold and dry conditions typical of winter
seasons promoting the transmission and virulence of COVID-19 (Tosepu et al. 2020;
Shi et al. 2020; Wu et al. 2020b). For example, the highest increase in daily infection
rates in the predominantly temperate northern hemisphere in Western Europe coincided
with dry and cold conditions (Miller et al. 2020). Modeling studies have also reported
inverse relationships between various metrics of COVID-19 transmission (e.g., the
basic reproductive number, R) and ambient temperature and relative humidity, although
variations occur among locations (Wang et al. 2020). Laboratory studies also show
that increasing temperature and humidity reduces the virulence of SARS viruses and
other coronaviruses (Casanova et al. 2010; Miller et al. 2020), while air pollution
increases virulence (Pansini and Fornacca 2020). These findings are consistent with
the observations and anecdotal evidence showing that influenza outbreaks in sub-Saharan
Africa and several other regions often occur in the winter season. However, a few
studies have reported results showing no relationship between COVID-19 outbreaks,
and weather and climatic drivers (Yao et al. 2020). For example, a regression analysis
of COVID-19 data covering 224 cities in China revealed no significant relationship
between COVID-19 transmission and increasing ultraviolet (UV) exposure, relative humidity,
or maximum and minimum ambient temperatures (Yao et al. 2020). Other studies have
shown that cases of certain coronavirus-related diseases such as Middle East respiratory
syndrome (MERS) continued to rise in the Middle East even when temperatures were as
high as 45 °C (Alshukairi et al. 2018). These mixed results suggest that climatic
and weather controls on COVID-19 could vary among regions and countries, possibly
due to varying control strategies and even transmission modes.
The bulk of sub-Saharan Africa experiences a predominantly tropical climate, and is
currently experiencing a winter period characterized by dry and cold conditions. Hence,
if the inverse relationship between temperature and humidity and COVID-19 transmission
and virulence is valid in sub-Saharan Africa, then the following trends in COVID-19
outbreak are expected: (1) a spike in COVID-19 cases in the winter period between
May and August this year, then followed by, (2) a drop in COVID-19 cases in the wet
and warm summer season as rising temperatures and humidity suppress COVID-19 transmission
and virulence. Recent observations seem to show that most countries in sub-Saharan
Africa have experienced rapid increases in COVID-19 coinciding with the current winter
period (Africa CDC 2020). However, at the country level, asynchronous COVID-19 outbreaks
may also occur due to contrasting climates among countries, and because different
countries implement mitigation measures to varying extents. Based on the anticipated
weather controls on COVID-19 transmission, one would have expected countries in sub-Saharan
Africa to tap into this knowledge to avoid the anticipated winter peak in COVID-19
infections by implementing strict social distancing measures during this period. Surprisingly,
several countries in sub-Saharan Africa are planning to open learning institutions
including schools, colleges, and universities at a time when peak COVID-19 outbreaks
are anticipated. The reasons and the scientific evidence informing such decisions
remain unclear, but the drive to relax or lift the lockdowns appear strong in several
countries in sub-Saharan Africa (Vaughan 2020; https://www.bbc.com/news/world-africa-52395976;
https://www.afro.who.int/news/who-urges-caution-countries-africa-ease-lockdowns).
The implications of such decisions on the number of COVID-19 cases and deaths remain
to be seen in most countries, but a surge in cases has been reported in some countries
(http://www.rfi.fr/en/africa/20200521-surge-in-cases-in-africa-after-lockdowns-lifted).
Currently, Africa lacks strong evidence relating COVID-19 outbreaks to climatic and
weather drivers. However, the role of climatic controls and teleconnections in human
disease outbreaks has been reported in Africa for several diseases including malaria
and Chikungunya virus, among others (Anyamba et al. 2012; Caldwell et al. 2020). A
question that arises in Africa is whether COVID-19 transmission dynamics will be coupled
to climatic and weather controls, and result in contrasting transmission patterns
in different climatic regions and countries. This is particularly interesting because
the climatic and current weather conditions in African countries are quite heterogeneous.
The dominant climates include wet and dry tropical, equatorial, tropical monsoon,
semi-desert or semi-arid, desert or hyper-arid and arid, and subtropical highland
climate (Pulsipher and Pulsipher 2008).
Climate or weather-based COVID-19 transmission models often assume that transmission
occurs via respiratory droplets (Miller et al. 2020). As discussed later, novel COVID-19
transmission dynamics in Africa may occur through the fecal–oral route, food contamination,
and vectors. Such novel COVID-19 transmission dynamics could present challenges to
current modeling approaches based on conventional transmission modes. Thus, the relationships
between COVID-19 transmission dynamics and climatic and weather controls in Africa
require further investigation. Such research should also aim to identify the best
predictors for estimating the transmission and virulence of COVID-19 and several co-infections
in Africa. However, Africa faces several research challenges including the lack of
reliable climatic and weather data, research funding, infrastructure, and even expertise
(Biagini 2016).
The critical role of the voice of the African research community
The unique socioeconomic settings, risk factors, and the potential for novel COVID-19
transmission call for a rethink on how current generic recommendations can be adapted
to suit the unique settings in Africa. In this regard, the scientific basis and validity
of the key assumptions inherent in current generic recommendations may need to be
validated against realities in Africa. In cases where such assumptions are considered
invalid, such generic COVID-19 mitigation measures may need to be re-contextualized,
adapted, and revised to better suit local realities. In some developed and low-income
regions, this process has been evident to some extent, where the research community
and several professional bodies have added their voice to the current discourse on
COVID-19. For example, in the UK, the Food Standards Agency (FSA-UK) produced an opinion
paper on the potential risks of COVID transmission via food (Oakenfull and Wilson
2020). In North America, the North American Alliance for the Study of Digestive Manifestations
of COVID-19 (GICOVID19.org) launched a research network and a clinical database collating
information characterizing the gastrointestinal and hepatic manifestations of COVID-19
from 30 centers in the USA and Canada (Aroniadis et al. 2020). Recently, the same
network published a joint scoping review on the current knowledge and research needs
on manifestations of COVID-19 in the human digestive system (Aroniadis et al. 2020).
Several other expert opinions exist in other countries and regions, including low-income
ones such as Latin America, the Caribbean region (Miller et al. 2020), and Asia (Fiesco-Sepúlveda
and Serrano-Bermúdez 2020; Kakimoto et al. 2020; Pung et al. 2020), among others.
Despite the rising number of COVID-19 cases in Africa, such learned opinions from
the African research community are largely missing. Only a few exceptions exist, focusing
on: (1) the need for collective action to combat COVID-19 in Africa (Nkengasong and
Mankoula 2020), and (2) a few others on the occurrence of COVID-19, and the preparedness,
and vulnerability of Africa (Gilbert et al. 2020; Kapata et al. 2020; Martinez-Alvarez
et al. 2020). Now that the COVID-19 wave has hit Africa, one would have expected an
influx of scientific expert opinions, viewpoints, commentaries, and even scoping and
horizon scanning reviews from the African research community. Horizon scanning reviews
provide foresight on emerging issues, and highlight critical issues to be addressed
on a subject, even in cases where experimental data are not available (Cuhls 2015).
It is in this regard that the voice of the African research community with intimate
knowledge of the African sociocultural norms and practices should be raised high in
the scientific discourse on COVID-19 in Africa. This is particularly true given that
Africa, like other regions, is home to several universities, research institutes,
and learned professional bodies spanning public health, the food industry, water and
sanitation, and social and behavioral sciences, among others. Surprisingly, barring
the current perspective, this process has been largely missing, and the voice of the
African research community on the issues highlighted here has been conspicuous by
its absence.
The reasons for the subdued voice of the African research community are unclear, but
may include the following: first, lack of expertise in infectious diseases of the
nature and magnitude of COVID-19. The fact that several African countries rely on
external experts for other infectious diseases such as Ebola virus (Gee and Skovdal
2017), and even waterborne diseases such as cholera (Ahmed et al. 2011), seems to
support this notion. Second, due to poor research funding and infrastructure, barring
South Africa and some countries in North Africa, Africa has one of the weakest research
systems in the world, and several studies have highlighted this limitation (Whitworth
et al. 2008; Chu et al. 2014). Thus, a weak scientific evidence base may exist on
infectious diseases such as COVID-19 to warrant authoritative expert opinions or viewpoints.
Finally, generic control measures from authoritative global agencies such as WHO (2020a,
b, c), and national health agencies from developed countries such as the Centers for
Disease Control and Prevention (CDC) in the USA (CDC 2020) and the National Health
Service (NHS) in the UK (https://www.nhs.uk/conditions/coronavirus-covid-19/), among
others, may be considered as “global best practices.” Given the advancement of scientific
research systems in such developed countries, the African scientific community could
be of the view that such global best practices are beyond reproach. Others may also
argue that Africa, including its research community, is now overwhelmed by COVID-19,
and hence any attempts or suggestions to change the mitigation strategy in the middle
of the crisis may confuse the public and cause loss of confidence, resulting in disastrous
health outcomes. However, the unique risk factors and challenges, as well as the potential
for novel COVID-19 transmission, point to the need for revisions of current guidelines.
Clearly, the opinions of the African scientific community should guide that process.
Thus, scope exists for the African voice to be heard with respect to COVID-19 in Africa.
Novel COVID-19 transmission dynamics and hotspots
Transmission modes
As reported in the scientific literature, the conventional transmission of SARS-CoV-2
occurs predominantly via the respiratory route and direct contact (WHO 2020b, c).
This understanding is also consistent with the positions of expert global health organizations
such as WHO and national health agencies such as NHS (UK) and CDC (USA). This transmission
mode is based on the fact that until recently, SARS-CoV-2 has been detected in swab
samples from the human respiratory system. However, recent studies detecting SARS-CoV-2
RNA in the human gastrointestinal system, feces, and wastewater point to other novel
transmission mechanisms. These novel transmission modes, including the fecal–oral
route, cross-contaminated food, and vector-mediated transmission, have attracted significant
research attention (Goh et al. 2020; Gu et al. 2020; Heller et al. 2020; Hindson 2020).
Here, the current evidence supporting each transmission mode is summarized in the
African context.
Fecal–oral COVID-19 transmission
The three key lines of evidence supporting the potential for fecal–oral transmission
of COVID-19 are summarized as follows.
SARS-CoV-2 in the human gut and feces
The human gastrointestinal tract is a hotspot reservoir for SARS-CoV-2, which is in
turn shed via feces from both symptomatic and asymptomatic infected persons (He et
al. 2020; Pan et al. 2020; Wu et al. 2020a; Young et al. 2020). SARS-CoV-2 shedding
periods as long as 33 days may occur in some infected persons even after SARS-CoV-2
tests on respiratory samples are negative (Wu et al. 2020a). Thus, SARS-CoV-2 shed
via feces are potentially released into the environment via open defecation, and through
wastewater and effluent discharge from on-site sanitation systems (e.g., pit latrines,
septic tanks) and municipal sewer systems.
(2)
Wastewater-based epidemiology
Wastewater-based epidemiology (WBE) relies on the surveillance of pathogens and their
proxies (e.g., SARS-CoV-2 RNA titers) in raw wastewater systems to gain insight into
the nature and magnitude of human infections (e.g., COVID-19) in a catchment (Ahmed
et al. 2020; Mallapaty 2020). Recent studies applying WBE have detected SARS-CoV-2
RNA in raw wastewater in Australia (Ahmed et al. 2020), France (Wurtzer et al. 2020),
Italy (La Rosa et al. 2020), the Netherlands (Medema et al. 2020), Spain (Randazzo
et al. 2020), and China (Zhang et al. 2020). For example, Ahmed et al. (2020) used
WBE combined with Monte Carlo simulation modeling and estimated that, based on the
SARS-CoV-2 RNA titers, a median of 171 to 1090 COVID-19-infected persons were in the
studied catchment. In China, SARS-CoV-2 RNA was detected in medical wastewater from
septic tanks even after disinfection with sodium hypochlorite at a dose of 800 g/m3
(Zhang et al. 2020). Thus, raw wastewater systems may harbor SARS-CoV-2, which may
subsequently undergo dissemination into drinking water and food sources (e.g., aquatic
foods). This recent evidence seems to contradict and supersede the earlier World Health
Organization position that “no studies exist on COVID-19 virus in drinking water and
sewage” (WHO 2020e). This contradiction can be attributed to the fact that research
on COVID-19 is rapidly evolving, and hence WHO updates may lag behind recent scientific
evidence.
(3)
SARS-CoV-2 shell structure and modeling evidence
Goh and colleagues investigated shell disorder of SARS-CoV-2 and other coronaviruses
using molecular methods and artificial intelligence to understand their persistence,
transmission routes, and virulence (Goh et al. 2020). Compared to other coronaviruses,
SARS-CoV-2 is unique in that it has a rigid or hard shell that confers environmental
persistence outside the human body and body fluids (Goh et al. 2020). For example,
evidence shows that SARS-CoV-2 may persist on surfaces for up to 6 to 9 days, which
increases the chance for transmission via the various modes (Van Doremalen et al.
2020; Wu et al. 2020a). Moreover, among the studied coronaviruses, SARS-CoV-2 had
the lowest shell disorder as evidenced by its low percentage of intrinsic disorder
(PID) (Goh et al. 2020). The low PID of SARS-CoV-2 points to its moderate potential
for transmission via both fecal–oral and respiratory routes. Thus, according to Goh
and co-workers (Goh et al. 2020), a combination of high stability conferred by a rigid
or hard shell and low shell disorder give further credence to potential fecal–oral
transmission. This notion is additionally supported by independent modeling studies
showing that a COVID-19 transmission model accounting only for respiratory and direct
contact transmission failed to explain the patterns of the Wuhan COVID-19 outbreak
(Danchin et al. 2020). A similar model accounting for the multiple transmission modes,
including the fecal–oral route, gave a better fit between the model results and the
observed data (Danchin et al. 2020). Taken together, these findings, when interpreted
with the risk factors and challenges, indicate that SARS-CoV-2 transmission via the
fecal–oral route could play a critical role in the proliferation of COVID-19 in Africa
and other low-income regions.
Transmission along the farm-to-fork food chain
The food chain includes production, harvesting, processing, logistics (storage and
transport), preparation, and serving (Oakenfull and Wilson 2020). Along this chain,
SARS-CoV-2 contamination may occur via two sources: (1) contaminated soils (e.g.,
sludge-amended soils) and irrigation water (e.g., wastewater), and (2) infected food
handlers. A few review studies have investigated the potential risk of COVID-19 transmission
via the food chain (Oakenfull and Wilson 2020; Li et al. 2020; Shariatifar and Molaee-aghaee
2019). For example, in the UK, the Food Safety Agency (FSA-UK) assessed the risk of
COVID-19 transmission via two routes, specifically consumption of: (1) foodstuffs
such as eggs, milk, meat, dairy, and blood products from infected food animals and
animal food products, and (2) cross-contaminated foodstuffs via (i) contaminated animal
products, (ii) non-animal foods, (iii) food contact materials, (iv) preparation surfaces,
and (v) infected persons involved in food preparation (Oakenfull and Wilson 2020).
FSA-UK concluded that the overall risk for COVID-19 transmission was negligible for
contaminated foodstuffs of animal origin, while that for the cross-contamination of
foodstuffs was very low (Oakenfull and Wilson 2020). In Singapore, Li et al. (2020)
also concluded that the risk of COVID-19 transmission via food was low. These studies
are based on the assumption that proper hygiene, quality control, and safety procedures
are strictly followed at each step in the food chain. However, this is often not the
case in Africa, where food hygiene, quality, and safety procedures are often non-existent
or weak and poorly enforced.
Given the lack of regular surveillance to determine infected persons in Africa, SARS-CoV-2
may be transmitted to food via sneezing, coughing, and handling during food processing,
packaging, and serving. In some African communities, familial dining practices commonly
involve family members sharing food from the same plate. In such settings, familial
fecal–oral transmission of COVID-19 may occur via contaminated hands. Transmission
via shared food has been reported in some studies conducted in Asia (e.g., Pung et
al. 2020). This is contrary to dining practices in developed countries, where each
person eats from his/her own plate, thereby minimizing the risk of cross-contamination
and familial transmission. These aspects, and vector-mediated contamination of food,
are not addressed in existing risk assessment studies conducted in developed countries
(e.g., Oakenfull and Wilson 2020). Hence, two points are noteworthy: (1) conclusions
based on studies conducted in developed countries cannot be directly extrapolated
to Africa without considering the unique African context and risk factors, and (2)
independent risk assessments for COVID-19 transmission via cross-contaminated food
are needed in Africa, taking into account its unique settings.
Vector-mediated transmission
In principle, two preconditions should exist for vector-mediated transmission of SARS-CoV-2
from environmental sources to the human receptor. First, viable and virulent SARS-CoV-2
should exist in environmental media accessible to the vector (e.g., household flies,
cockroaches, rodents). In this case, fecal matter from on-site sanitation systems,
open defecation, and wastewater may act as SARS-CoV-2 reservoirs for vector-mediated
food contamination. Second, such environmental media must attract vectors, which then
act as a host and/or come into direct contact with the SARS-CoV-2, and subsequently
transmit it to humans directly or via intermediate media such as food. The latter
scenario is most likely, where vectors such as household flies, cockroaches, and rodents
are attracted to and frequent fecal-contaminated sources and then transfer the SARS-CoV-2
to human food. This mechanism was proposed in earlier studies focusing on the fecal–oral
transmission hypothesis (Bonato et al. 2020; Heller et al. 2020; Yeo et al. 2020).
Direct evidence documenting COVID-19 transmission via vectors is still limited. In
addition, studies investigating potential human health risks via food contamination
in developed countries (Li et al. 2020; Oakenfull and Wilson 2020) overlooked vector-mediated
transmission. This is obviously because such a transmission mechanism is regarded
as highly unlikely in developed countries due to strict food hygiene, quality, and
safety standards. Evidence drawn from Africa and elsewhere in low-income regions shows
that several vectors, including rodents and houseflies, that are attracted to fecal
matter, on-site sanitation systems, and even human cadavers are also frequently found
in households (Songe et al. 2017; Akter et al. 2020; Al-Khalifa et al. 2020). One
study conducted in Zambia showed that houseflies which infested fish in open food
markets acted as vectors for the transmission of antibiotic-resistant pathogenic Salmonella
and Escherichia coli (Songe et al. 2017). Therefore, in light of the poor food hygiene
and safety standards in Africa, vector-mediated COVID-19 transmission via the fecal
matter–food–human pathway cannot be ruled out. Hence, this transmission mode warrants
further research in Africa, focusing on food in households, open food markets, and
street-vended foods, especially at the point of consumption.
COVID-19 transmission hotspots
Considering the potential multiple transmission modes of COVID-19 highlighted here,
community settings where overcrowding is common, and shared water and sanitation facilities
constitute potential COVID-19 transmission hotspots. In infectious disease epidemiology,
hotspots are spatial or community clusters with unusually high disease burden or transmission
efficiency relative to other environments (Lessler et al. 2017). Thus, potential COVID-19
hotspots include: (1) prisons and correctional services facilities, (2) overcrowded
quarantine centers and health care facilities, (3) informal settlements such as slums,
squatter camps, and refugee camps, and (4) even learning institutions such as schools,
colleges and universities. In such settings, community or shared water and sanitation
facilities are often used, and social distancing could be problematic due to overcrowding.
With respect to shared water facilities, women and girls are particularly vulnerable
due to their roles in household water provision, as they frequently spend prolonged
periods in long queues at shared water points. Women and girls are also often responsible
for cleaning of sanitation facilities, risking exposure to COVID-19 via aerosols and
fomites from shared sanitation facilities.
Prison and correctional facilities are potential COVID-19 transmission hotspots because
they are often overcrowded and have poor water and sanitation facilities (UN 2020).
In some prisons and correctional facilities, a typical cell shared among several inmates
consists of a toilet-cum-bathroom and bedroom combined in one unit. Due to excessive
overcrowding, high incidences of infectious diseases such as tuberculosis have been
reported in several prisons and correctional facilities in Africa (O’Grady et al.
2011; Jaquet et al. 2016). Moreover, as the number of COVID-19 cases, returnees, and
deportees increases, overcrowding in quarantine centers is likely to occur. As in
prisons and correctional services facilities, shared water and sanitation facilities
are common in quarantine centers. Media reports show that high rates of COVID-19 cases
have been reported in prisons and quarantine centers in Africa and other low-income regions
due to overcrowding and unhygienic conditions, pointing to the possibility of community
transmission (Schlein 2020; UN 2020). Yet most people in prisons and correctional
services, slums, squatter camps, and refugee settlements are vulnerable, because they
have no reliable source of income or livelihood. Such vulnerable people are often
excluded in COVID-19 programs such as diagnostic testing, formulation of policies,
and control strategies, and even allocation of scarce resources such as PPE. Hence,
government and humanitarian agencies should ensure that such vulnerable people in
these and other settings are not excluded in the fight against COVID-19. Current WHO
(2020b, c) guidelines and even national guidelines and control measures on COVID-19
often exclude these potential transmission hotspots and vulnerable groups.
Novel COVID-19 transmission calls for additional safeguards
The unique risk factors, challenges, and potential for novel transmission, coupled
with the infectious nature of COVID-19, are herein termed “dangerous liaisons.” These
dangerous liaisons point to potential complex COVID-19 transmission dynamics, resulting
in potentially more adverse human health outcomes in Africa relative to developed
countries. Yet, currently, incontrovertible scientific evidence linking the novel
transmission modes to COVID-19 outbreaks is still lacking. However, the lack of evidence
attributable to absence of studies on the subject should not be misinterpreted as
absence of human health risks. In this regard, based on the lines of evidence summarized
here, COVID-19 transmission via the fecal–oral route, contaminated food, and vectors
cannot be ruled out in Africa. Thus, given the severity and adverse human health outcomes
associated with COVID-19, Africa, and possibly other low-income regions, may need
to assume the “worst-case scenario” and adopt the precautionary principle. In simple
terms, the precautionary principle implies that in the absence of a comprehensive
understanding of the transmission dynamics of COVID-19, Africa should assume the worst-case
scenario and take appropriate precautions. These precautions entail adapting, re-contextualizing,
and revising existing generic control measures as well as implementing additional
safeguards to suit African settings. Specifically, the following recommendations are
proposed:
Reliable clean drinking water provision
The provision of reliable and clean drinking water where available, and/or treating
drinking water via boiling and disinfection using chlorination, should be an integral
part of the COVID-19 control measures (WHO 2020e). Water disinfection reduces the
risk of fecal–oral transmission, because SARS-CoV-2 is sensitive to temperatures above
65 °C and biocidal agents such as chlorine and hypochlorite. Reliable water supplies
also reduce community transmission via overcrowding at community shared water points.
Clean water provision also reduces the risk of waterborne co-infections such as cholera
and typhoid, and enables communities to adhere to social distancing measures such
as lockdowns.
(2)
Improved sanitation and hygiene practices
Proper sanitation should be urgently provided in areas where it is currently lacking.
Particular attention should be paid to informal settlements, slums, squatter camps,
and refugee camps. This is critical to avoid open defecation and subsequent potential
transmission of COVID-19 via vectors. In the case of shared sanitation facilities,
the availability of adequate facilities must be ensured to avoid overcrowding. The
cleaning of such shared sanitation facilities should not be the sole responsibility
of women and girls. Rather, the responsibility should be shared fairly, between women
and girls on the one hand, and their male counterparts on the other hand.
(3)
Food hygiene, quality control, and safety
Proper food hygiene, handling, and safety procedures including washing and proper
cooking are critical to reducing the potential risk of COVID-19 transmission via contaminated
food along the farm-to-fork chain. Unhygienic practices such as informal vending of
food in open markets and streets, and public transport should be prohibited. Human
food surveillance systems should be strengthened to ensure that foods from sick animals
and potentially contaminated sources do not enter the human food chain. Proper cooking
of food is critical, since SARS-CoV-2 is sensitive to temperature. Moreover, foods
from potentially contaminated sources such wastewater irrigation and wastewater-based
aquacultural systems should be avoided during a COVID-19 outbreak.
(4)
Protecting vulnerable people in COVID-19 transmission hotspots
Women and girls using shared water and sanitation facilities, prisoners and workers
in the prison and correctional facilities, and returnees, deportees, and workers in
quarantine centers constitute vulnerable groups associated with COVID-19 transmission
hotspots. To minimize the risk of COVID-19 transmission, the following control measures
are recommended:
(i)
Hand-washing facilities, including sanitizers, are needed at shared water and sanitation
facilities such as boreholes, wells, and toilets. Clear signage informing the public
of the need to wash hands before and after using such facilities, and even to clean
water abstraction devices (e.g., handles), should be included at these shared facilities.
(ii)
Overcrowding should be avoided in prison and correctional, and quarantine facilities
during COVID-19 outbreaks. In both prison and correctional, and quarantine facilities,
inmates should be screened before being accommodated in such facilities. Moreover
regular and frequent COVID-19 screening will be required to ensure that infected people
are accommodated separately from the non-infected ones.
(5)
Revising current guidelines and raising awareness
The highlighted additional safeguards may necessitate the revision and adaptation
of current guidelines to reflect the unique African settings. Consequently, such additional
safeguards and revisions will need to be systematically communicated to the various
stakeholders without causing panic and confusion. This requires raising public awareness
on the additional safeguards through well-structured educational campaigns, pamphlets,
and media updates. Besides mitigating COVID-19, the proposed additional safeguards
are critical for safeguarding human health against other human co-infections in Africa
including waterborne diseases. However, it remains unclear whether African governments
and international and national agencies are prepared to embrace these realties and
adjust and revise the current mitigation strategies accordingly. This is because Africa
is now in the midst of a COVID-19 crisis, and some may argue that a shift in the control
strategy could cause loss of confidence and create confusion among stakeholders.
Concluding remarks
The current perspective highlights how the interactions of COVID-19 transmission and
infectivity, and the inherent risk factors and challenges in Africa, could culminate
in complex transmission dynamics and adverse human health outcomes. It was demonstrated
that while the recommendations of global health institutions such as WHO are premised
on respiratory and direct contact transmission modes, novel transmission may also
play a key role in COVID-19 transmission in Africa. Thus, COVID-19 transmission via
the fecal–oral route, vectors, and food contamination in the farm-to-fork food chain
cannot be ruled out. The potential for fecal–oral, vector-mediated, and food transmission
modes adds another layer of complexity to COVID-19 transmission and control in Africa.
The reasons for this were highlighted, and include: (1) poor water and sanitation
infrastructure, (2) poor hygiene practices that increase the risk of human exposure,
and (3) poor food hygiene, quality, and safety procedures in the food chain. Thus,
unless additional safeguards are implemented, COVID-19 infection and mortality rates
in Africa could be higher than current predictions premised solely on respiratory
and direct contact transmission. Therefore, as a precaution to reduce the risk of
novel transmission and to protect human health, the following additional safeguards
and recommendations were proposed: (1) strengthen the water, sanitation, and hygiene
(WASH) component through clean water provision and proper sanitation to avoid open
defecation; (2) engage in good food hygiene and safety practices along the farm-to-fork
food chain, including washing and proper cooking of food, and avoid or ban open market-
and street-vended foods; (3) increase public awareness of the need for the additional
safeguards that are unique to Africa; and (4) pay particular attention to COVID-19
transmission hotspots and vulnerable people such as prisoners, women, children, and
those in quarantine centers, slums, squatter camps, and refugee camps. The proposed
safeguards are not meant to replace current mitigation measures, but rather are additional
and complementary to current measures based on the use of PPE, social distancing,
and frequent hand washing.