Epidemiology of Rotavirus in Humans, Animals, and the Environment in Africa: A Systematic Review and Meta-analysis

Abstract

Background

Globally, rotavirus infections are the most common cause of diarrhea-related deaths, especially among children under 5 years of age. This virus can be transmitted through the fecal-oral route, although zoonotic and environmental contributions to transmission are poorly defined. The purpose of this study is to determine the epidemiology of rotavirus in humans, animals, and the environment in Africa, as well as the impact of vaccination.

Methods

We searched PubMed, Web of Science, Africa Index Medicus, and African Journal Online, identifying 240 prevalence data points from 224 articles between 2009 and 2022.

Results

Human rotavirus prevalence among patients with gastroenteritis was 29.8% (95% confidence interval [CI], 28.1%–31.5%; 238 710 participants), with similar estimates in children under 5 years of age, and an estimated case fatality rate of 1.2% (95% CI, .7%–2.0%; 10 440 participants). Prevalence was estimated to be 15.4% and 6.1% in patients with nongastroenteritis illnesses and apparently healthy individuals, respectively. Among animals, prevalence was 9.3% (95% CI, 5.7%–13.7%; 6115 animals), and in the environmental water sources, prevalence was 31.4% (95% CI, 17.7%–46.9%; 2530 samples).

Discussion

Our findings highlight the significant burden of rotavirus infection in Africa, and underscore the need for a One Health approach to limiting the spread of this disease.

We performed a systematic review and meta-analysis of studies of rotavirus in Africa and found high prevalences in human, animal, and environmental water sources, underscoring the need for a One Health approach to limiting the spread of this disease.

Diarrheal illness is one of the most common diseases in humans and is the fifth highest cause of death among children under 5 years old globally [1]. A wide range of enteric pathogens can cause diarrhea [2], but rotaviruses are responsible for more than 250 million cases per year in children under the age of 5 year, and are ranked third on the list of pathogens that contribute to childhood death [1, 3], accounting for an estimated 185 400 deaths annually in children under 5 years old [4]. Rotavirus can also be a significant cause of morbidity and mortality in young animals, including mammalian and avian species, specifically livestock and poultry [5], including swine, cattle, calves, piglets, and foals [6, 7]. In these animals, rotavirus infection is associated with acute diarrheal illness, which can result in severe economic losses, particularly in intensively reared livestock and poultry industries [8].

Rotavirus is a highly infectious virus that can be transmitted through various routes, including direct contact with infected individuals, ingestion of contaminated food or water, and exposure to contaminated surfaces [9]. In humans, rotavirus is primarily transmitted through the fecal-oral route, while in animals, it can be transmitted through the consumption of contaminated feed or water, contact with infected animals, and exposure to contaminated environments [10]. The virus can also persist in the environment for extended periods, contributing to its widespread distribution and transmission [11, 12]. The genetic heterogeneity of rotavirus across different strains and its capacity to infect a broad range of species suggests that this virus can generate highly virulent variants through gene reassortments and be transmitted to humans as a zoonotic disease [8]. There is evidence of occasional outbreaks caused by animal strains of rotavirus, particularly in environments where humans and animals are in close contact, such as farms or animal exhibitions, although these outbreaks generally affect a limited number of individuals and are not as widespread as outbreaks originating from human strains [5, 6].

Control of rotavirus transmission in humans requires a multifaceted approach that includes sanitation, good hand washing, and other hygienic measures [13, 14]. Water, sanitation and hygiene (WASH) programs, which aim to interrupt fecal-oral transmission pathways, have the potential to prevent most diarrheal diseases, including rotavirus [15]. In 2009, the World Health Organization (WHO) recommended the introduction of 2 licensed rotavirus vaccines (Rotarix, GlaxoSmithKline and RotaTeq, Merck) into national childhood immunization programs [16]. Despite vaccine coverage of 74% (as of July 2020) in African countries [17], rotavirus remains the most common pathogen causing diarrhea in children younger than 5 years [18]. While recent systematic reviews on rotavirus prevalence in individual countries [19], and Northern Africa [20], have been published, one that covers the entire continent of Africa is lacking. In addition, with increasing recognition of the contribution of animal and environmental sources of transmission under a One Health perspective, an updated comprehensive picture of the epidemiology of rotavirus in Africa can inform public health policies and interventions.

METHODS

The systematic review was defined, conducted, and reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines [21] (Supplementary Table 1). Methodologically, we followed a predefined protocol and registered the review in PROSPERO (CRD42021246581).

Data Source and Selection Process

We searched PubMed, Web of Science, African Index Medicus, and African Journal Online on 6 April 2021, and updated our search on 17 December 2022. In both English and French, we searched with the key words covering the condition “rotavirus” and country and region-specific names for geographic areas in Africa (Supplementary Table 2). Other relevant studies were found by manually searching the eligible studies’ bibliographies.

Eligibility Criteria

We reviewed studies reporting rotavirus detection in humans, animals, and in the environment in Africa. As rotavirus circulates seasonally, human studies were restricted to those lasting at least 1 year [22]. We included studies published after 2009, when rotavirus vaccines were first introduced in Africa [23]. Interventional (clinical trials) and observational (cohort, control, and cross-sectional) studies were included. Rotavirus case fatality rates (CFR) in humans were calculated using subjects with active rotavirus detection. We excluded duplicates and studies without abstracts or full texts.

Methods for Data Extraction and Quality Assessment

At least 2 of the following authors independently reviewed and extracted data from each of the articles included in this review: A. B. N., D. S. M., G. M., J. T. E. B., and S. K. We retrieved the following data from included studies: the first author's name, the year the study was published, the design of the study, the time when data were collected, the sampling method, the setting, the hospitalization status, the duration of the study, the type of population (human, animal, or environment), the rotavirus species, the period of introduction of the vaccine (before or after vaccine introduction era), the age range, the detection assay, the sample type, the number of samples tested, the number of positives, and the number of deaths among the positives. In animal studies with participants <10 or grouped for laboratory testing, we extracted the species positive for rotavirus. Study quality was assessed using the tool developed by Hoy et al [24] (Supplementary Table 3). Disagreements were resolved through discussion and consensus.

Data Synthesis and Analysis

All statistical analyses were conducted using the meta (version 4.18–2) and metafor (version 3.0–2) packages in R software version 4.0.3 [25]. Several indicators were used to classify countries, including United Nations (UN) Sustainable Development Goal regions, World Bank Income Groups [26], WHO regions [27], and WHO mortality strata [28]. Human populations were classified into apparently healthy individuals, patients with gastroenteritis, and patients with diseases other than gastroenteritis, for the determination of rotavirus prevalence. Environmental samples were categorized into drinking vessels, food sources, and water sources, including groundwater, drinking water, surface water, treated wastewater, and untreated wastewater.

We defined prevalence as the proportion of humans, animals, or environmental samples positive for rotavirus amongst the given sample population. Animals were sorted by taxonomic order whenever possible. Vaccine introduction dates were retrieved from the GAVI website. We classified the studies as before or after vaccine introduction based on the recruitment period. When possible, we separated prevalence data from studies conducted before and after vaccine introduction. A prevaccination period was assigned to all studies conducted in countries where vaccines have not yet been introduced or where the publication year preceded the vaccine's introduction date. When detecting rotavirus using multiple methods in the same set of samples (not solely for confirmation of positive results), we chose the detection method with the highest proportion of positive results. The proportions of individual studies were pooled using a random-effect meta-analysis [29, 30]. Alongside 95% confidence intervals (CIs), an estimate of the precision of the observed effect size, we also calculated prediction intervals (PIs) to provide a range in which the true effect size of a potential new study could fall. I² statistics and Cochran's Q test [29] were used to assess heterogeneity between studies. In stratified analyses, heterogeneity was assessed according to study design, sampling strategy, setting, hospitalization status, time of sample collection, countries, WHO Regions, UN Regions, Sustainable Development Goal regions, World Bank Income Groups, WHO mortality strata, vaccination introduction status, vaccination introduction year, vaccination introduction era, rotavirus type, human population groups, animal order, detection assay, target detected, and sample type. We only performed subgroup analysis on covariate categories with at least 3 prevalence data points. Egger's funnel plots and regression tests were used to assess publication bias [31].

RESULTS

Identification of Studies

Our search of the 4 databases identified 2905 articles. We removed 981 duplicates (Supplementary Figure 1), excluded 1343 articles that did not meet the inclusion criteria based on assessment of titles and abstracts, and excluded 357 articles based on full-text review (Supplementary Table 4). The remaining 224 articles met the criteria for this systematic review and meta-analysis (Supplementary References).

Characteristics of Included Studies

Detailed characteristics, individual characteristics, and risk of bias assessments are summarized in Supplementary Tables 5–7. In the included studies, participants were recruited between 1996 and 2021, and the studies were published between 2009 and 2022. A majority of the 224 included studies used cross-sectional designs (92.0%; n = 206), nonprobability sampling (91.5%; n = 205), and prospective recruitment (98.2%; n = 220). Most of the studies included were conducted in hospital settings (78.6%; n = 176), and in Eastern Africa (35.7%; n = 80) or Western Africa (25.9%; n = 58) as classified by UN Regions definition. Lower-middle income countries were the most represented (56.7%; n = 127), followed by low-income countries (31.7%; n = 71). By WHO mortality strata, Africa Stratum E (Afr-E, high child and very-high adult mortality) countries was the most represented stratum (47.3%; n = 106), followed by Stratum D (Afr-D, high child and high adult mortality) countries (33.5%; n = 75). Most studies covered the period before the introduction of the vaccine (67.0%; n = 150). Most of the included studies involved humans (81.7%; n = 183), with gastroenteritis being the most common condition (65.6%; n = 147) and children under 5 years being the most represented (71.9%; n = 161). Rotavirus was detected in stool primarily by enzyme immunoassay (66.0%; n = 148). Only a few studies described the type of rotavirus (A to G) detected. Most studies were at moderate risk of bias (91.5%; n = 205).

Case Fatality Rate of Rotavirus Infections in Humans

The CFR was estimated from 10 440 rotavirus-positive humans (16 included studies, Supplementary Figure 2). All studies for determining CFR involved children aged 0–5 years who were hospitalized with gastroenteritis and most were prior to the introduction of vaccines. A combined CFR of 1.2% (95% CI, .7%–2.0%) was estimated (Figure 1). Following vaccine introduction, only 2 studies were conducted in South Africa with a CFR of 0.9% (95% CI, .2%–1.9%; 614 participants; Table 1). In the period prior to vaccine introduction, CFR was 1.4% (95% CI, .8%–2.2%; 9826 participants).

Figure 1.

Case fatality rate estimates of rotavirus infections in humans in Africa, 2009–2022. Full citations to studies cited are found in Supplemental Materials Additional References.

Table 1.

Case Fatality Rate and Prevalence of Rotavirus in Humans, Animals, and Environment in Africa by Vaccination Era

	Prevalence, % (95% CI)	95% Prediction Interval	No. of Studies	No. of Samples	H (95% CI)a	I² (95% CI)b	P Heterogeneity	P Difference Subtypes
Rotavirus CFR in humans
Prevaccination era	1.4 (.8–2.2)	0–5.1	14	9826	2.5 (2–3.1)	83.8 (74.2–89.8)	<.001	.496
Postvaccination era	0.9 (.2–1.9)	NA	2	614	1	0	.331
Rotavirus prevalence in patients with gastroenteritis
Prevaccination era	31.1 (29–33.2)	8.7–59.7	167	178906	9.6 (9.3–9.9)	98.9 (98.9–99)	<.001	.01
Postvaccination era	26.4 (23.7–29.3)	8.4–50	59	59804	7.7 (7.3–8.1)	98.3 (98.1–98.5)	<.001
Rotavirus prevalence in patients with nongastroenteritis illnesses
Prevaccination era	15.4 (7.7–25)	0–55.9	6	2163	5.4 (4.3–6.9)	96.6 (94.6–97.9)	<.001	.981
Postvaccination era	15.5 (4–32.5)	NA	2	612	3.8 (2.1–7)	93.2 (77.8–97.9)	<.001
Rotavirus prevalence in apparently healthy individuals
Prevaccination era	6.4 (3.9–9.5)	0–28.8	28	13774	6.4 (5.9–7)	97.6 (97.1–98)	<.001	.651
Postvaccination era	4.5 (0–14.3)	0–75.4	4	4794	9.3 (7.5–11.5)	98.8 (98.2–99.2)	<.001
Rotavirus prevalence in animals
Prevaccination era	9 (4.3–14.9)	0–53.8	35	4028	5 (4.5–5.5)	96 (95.1–96.7)	<.001	.868
Postvaccination era	9.7 (3.2–18.7)	0–58.9	18	1184	3.9 (3.3–4.6)	93.4 (91–95.2)	<.001
Rotavirus prevalence in environmental water sources
Prevaccination era	35.6 (20.4–52.3)	0–98.9	19	2268	7.9 (7.1–8.7)	98.4 (98–98.7)	<.001	.646
Postvaccination era	25.8 (.9–65)	0–100	5	177	5.1 (3.8–6.6)	96.1 (93.2–97.7)	<.001

Abbreviations: CFR, case fatality rate; CI, confidence interval; NA, not applicable.

^a H is a measure of the extent of heterogeneity, a value of H = 1 indicates homogeneity of effects and a value of H > 1 indicates a potential heterogeneity of effects.

^b I ² describes the proportion of total variation in study estimates that is due to heterogeneity, a value > 50% indicates presence of heterogeneity.

Prevalence of Rotavirus Infections in Patients With Gastroenteritis

Among studies in 39 countries spanning all African regions (175 included studies with 238 710 individuals), the estimated combined prevalence in patients with gastroenteritis was 29.8% (95% CI, 28.1%–31.5%) with similar estimates when limited to children <5 years of age (30.8%; 95% CI, 29.0%–32.6%) (Table 2, Figure 2, and Supplementary Figure 2). The prevalence of rotavirus in the postvaccination era was 26.4% (95% CI, 23.7%–29.3%; 59 studies with 59 804 participants), which was significantly lower (P = .01; Table 1) than that in the prevaccination era (31.1%; 95% CI, 29.0%–33.2%; 167 studies with 178 906 participants).

Table 2.

Summary of Meta-analysis Results for Epidemiology of Rotavirus in Humans, Animals, and Environment in Africa

	Prevalence, % (95% CI)	95% Prediction Interval	No. of Studies	No. of Participants	H (95% CI)a	I² (95% CI)b	P Heterogeneity
Rotavirus CFR in humans
Overall	1.3 (.7–2)	0–4.6	16	10440	2.3 (1.9–2.9)	81.5 (71.1–88.2)	< .001
Cross-sectional	1.3 (.7–2.1)	0–4.8	15	9900	2.4 (1.9–3)	82.7 (72.6–89)	< .001
Birth to 5 y	1.3 (.7–2)	0–4.6	16	10440	2.3 (1.9–2.9)	81.5 (71.1–88.2)	< .001
Prevalence in patients with gastroenteritis
Overall	29.8 (28.1–31.6)	8.5–57.3	226	238710	9.2 (9–9.5)	98.8 (98.8–98.9)	< .001
Cross-sectional	30.5 (28.7–32.3)	9–57.9	206	223020	9.3 (9.1–9.5)	98.8 (98.8–98.9)	< .001
Birth to 5 y	30.8 (29–32.6)	9.5–57.8	204	218872	9.1 (8.9–9.4)	98.8 (98.7–98.9)	< .001
Low risk of bias	23.8 (18.3–29.8)	4.3–52.4	16	14641	8.1 (7.3–9)	98.5 (98.1–98.8)	< .001
Prevalence in patients with nongastroenteritis illnesses
Overall	15.4 (9.2–22.9)	0.2–46.6	8	2775	4.9 (4–6.1)	95.9 (93.7–97.3)	< .001
Cross-sectional	23.4 (17.5–29.9)	2.7–55.7	4	1578	2.8 (1.8–4.3)	86.8 (68.3–94.5)	< .001
Birth to 5 y	13.9 (6.8–22.9)	0–52.5	6	2421	5.6 (4.5–7.1)	96.8 (95–98)	< .001
Low risk of bias	8.4 (3.8–14.5)	NA	1	107	NA	NA	1
Prevalence in apparently healthy individuals
Overall	6.1 (3.9–8.8)	0–26.9	32	18568	6.7 (6.1–7.2)	97.7 (97.3–98.1)	< .001
Cross-sectional	6.7 (3.9–10.2)	0–29.3	22	12159	6.5 (5.8–7.2)	97.6 (97.1–98.1)	< .001
Birth to 5 y	7.2 (4.4–10.5)	0–28.9	23	15271	6.9 (6.3–7.6)	97.9 (97.5–98.3)	< .001
Low risk of bias	11.3 (5.8–18.3)	0–41.5	7	3190	5.1 (4–6.3)	96.1 (93.9–97.5)	< .001
Prevalence in animals
Overall	9.4 (5.7–13.7)	0–50.2	57	6115	4.6 (4.3–5)	95.4 (94.6–96)	< .001
Cross-sectional	9.4 (5.7–13.7)	0–50.2	57	6115	4.6 (4.3–5)	95.4 (94.6–96)	< .001
Low risk of bias	5.2 (0–18.4)	0–100	3	840	5.5 (3.9–7.9)	96.7 (93.3–98.4)	< .001
Prevalence in environmental water sources
Overall	31.3 (17.6–46.8)	0–98.4	24	2530	7.8 (7.1–8.5)	98.4 (98.1–98.6)	< .001
Cross-sectional	31.3 (17.6–46.8)	0–98.4	24	2530	7.8 (7.1–8.5)	98.4 (98.1–98.6)	< .001

Abbreviations: CFR, case fatality rate; CI, confidence interval; NA, not applicable.

^a H is a measure of the extent of heterogeneity, a value of H = 1 indicates homogeneity of effects and a value of H > 1indicates a potential heterogeneity of effects.

^b I ² describes the proportion of total variation in study estimates that is due to heterogeneity, a value > 50% indicates presence of heterogeneity.

Figure 2.

Pooled prevalence of rotavirus in humans in Africa, 2009–2022.

Prevalence of Rotavirus Infections in Patients With Nongastroenteritis Illnesses

Among studies in 6 countries, involving a total of 2775 individuals, the combined prevalence of rotavirus in individuals with nongastrointestinal illnesses was found to be 15.4% (95% CI, 9.1%–22.8%), with similar estimates in children under 5 years of age (13.9%; 95% CI, 6.8%–22.9%) (Table 2 and Supplementary Figure 2).

Prevalence of Rotavirus Infections in Apparently Healthy Individuals

Among 31 studies from 17 different countries, including 18 568 participants, prevalence of rotavirus among apparently healthy individuals was 6.1% (95% CI, 3.9%–8.8%), with similar estimates for children under the age of 5 years (7.2%; 95% CI, 4.4%–10.5%; Table 2 and Supplementary Figure 2). The prevalence in the postvaccination era, 4.5% (95% CI, 0%–14.3%) across 4 studies with 4794 participants, was not significantly different (P = .651; Table 1) than the prevalence in the prevaccination era, which was 6.4% (95% CI, 3.9–9.5) across 28 studies with 13 774 participants.

Prevalence of Rotavirus Infections in Animals

There were 23 included studies that assessed rotavirus prevalence in 6115 animals in 14 countries. Several animal orders are included in the estimated prevalence, primarily Artiodactyla and Chiroptera. Animals had an estimated combined prevalence of 9.3% (95% CI, 5.7%–13.7%) with a significant difference depending on the order of animals (Figure 3 and Supplementary Figure 3).

Figure 3.

Pooled prevalence of rotavirus in animals in Africa, 2009–2022.

Prevalence of Rotavirus in the Environment

Due to only 2 studies examining rotavirus prevalence in environmental sources that were not related to environmental water, we limited our analysis to its prevalence in environmental water sources. Rotavirus prevalence in environmental water sources was assessed in 18 studies from 10 African countries (2530 water samples), with varying prevalence depending on source, and with an estimated combined prevalence of 31.4% (95% CI, 17.7%–46.9%; Figure 4).

Figure 4.

Pooled prevalence of rotavirus in environment in Africa, 2009–2022. Full citations to studies cited are found in Supplemental Materials Additional References.

Sensitivity, Heterogeneity, and Publication Bias Analyses

We found substantial heterogeneity in all estimates (I² > 50%; Table 1). Using only the best prevalence study design (cross-sectional) and low risk of bias studies, sensitivity analysis revealed robust results. No publication bias was observed in the estimates of CFR in humans (P = .090), and rotavirus prevalence in patients with gastroenteritis (P =.069), patients with nongastroenteritis illnesses (P = .540), apparently healthy individuals (P = .114), animals (P = .166), and environment (P = .244; Supplementary Figures 4–7).

Subgroup Analyses

We performed subgroup analyses on covariate categories with at least 3 prevalence data points (Supplementary Table 8). Notably, in patients with gastroenteritis, the UN region with the highest pooled prevalence was Middle Africa (41.5%; 95% CI, 35.5%–47.5%), followed by Western Africa (31.8%; 95% CI, 28.4%–35.2%), while the same 2 regions had the highest pooled prevalence in studies of apparently healthy individuals (7.8% and 8%, respectively). Rotavirus prevalence among ambulatory patients with gastroenteritis was 25.0% (95% CI, 17.8%–33%) while hospitalized patients had a higher prevalence of 33.2% (95% CI, 31.1%–35.4%). In both studies of patients with gastroenteritis and with nongastroenteritis illnesses, studies with a cross-sectional design reported higher prevalence than those with a case-control design. In studies of prevalence in animals, we found a higher prevalence in lower–middle-income countries (18.5%, 95% CI, 9.7%–29.2%) compared to low-income countries (P = .022), with the highest prevalences in the Eastern Mediterranean (42.2%; 95% CI, 20.7%–65.3%) and Northern Africa (42.2%; 95% CI, 20.7%–65.3%) UN regions.

DISCUSSION

Rotavirus is a major cause of morbidity and mortality due to diarrheal illness in Africa, and understanding its burden and distribution, including in that of animal and environmental reservoirs, is crucial for effective control and prevention strategies [12, 32]. Here, we report the findings of a systematic review and meta-analysis of the prevalence of rotavirus in humans, animals, and the environment in Africa, which included 224 articles corresponding to 240 prevalence data points between 2009 and 2022. We estimated rotavirus prevalence in patients with gastroenteritis to be 29.8%, which was higher in the prevaccine-introduction era compared to the postvaccine-introduction era. The prevalence was estimated at 15.4% and 6.1% in patients with nongastroenteritis illnesses and apparently healthy individuals, respectively. Our findings highlight the significant burden of this infection on public health in the region.

Our estimate of the prevalence of rotavirus in patients with gastroenteritis in Africa across all age groups (29.8%) is consistent with the findings of a previous systematic review conducted in the region [18]. The prevalence estimate of 30.8% in children under 5 years old with gastroenteritis is particularly concerning, as this age group is the most vulnerable to severe illness and death due to rotavirus infection [33]. Rotavirus has long been recognized as a leading cause of infection and hospitalization in children under 5 years [34], and our findings are consistent with recent multicontinent studies showing that this continues to be the case both in Africa and worldwide [35]. The prevalence in young children could be partially attributed to their immature immune system response [36, 37]. Our findings highlight the need for tailored interventions for children under 5 years old. Effective interventions may include vaccination programs [38, 39], improvements in sanitation and hygiene practices, and increased access to clean drinking water [13, 15, 40]. Given the significant burden of rotavirus infections in Africa, it is crucial to prioritize the implementation of these interventions to reduce the morbidity and mortality associated with this disease. Taken together, these studies highlight the significant morbidity and mortality associated with rotavirus, especially in populations with limited access to clean water and sanitation [12, 41].

We found a combined CFR of 1.2%, with no significant difference between pre- and postvaccination eras. This is considerably higher than the global estimate reported by Asare et al [42]. Timely treatment, primarily through the use of oral rehydration therapy to replace lost fluids and electrolytes [43], is crucial to reduce both morbidity and mortality of diarrheal illnesses such as in rotavirus infections.

Our results demonstrate significant differences in the prevalence of rotavirus between countries and UN-defined regions. The low rate of childhood vaccination and its late introduction into the national immunization programs of some African countries may explain why the prevalence in the postvaccination era was not lower. However, the impact of the rotavirus vaccine in sub-Saharan Africa remains significant. Prior studies have demonstrated that the introduction of rotavirus vaccine played a large role in reducing the burden of rotavirus-associated diarrhea in sub-Saharan Africa [33, 44, 45], highlighting the importance of its inclusion in national vaccination programs [42]. The higher prevalence of rotavirus in Middle and Western Africa suggests that targeted interventions, such as vaccination or improved sanitation and hygiene measures, may be particularly important in these regions [33, 44, 45]. Such interregional differences are likely due to disparities in access to clean water and sanitation, and availability of vaccination programs or improved water and sanitation infrastructure. In expanded immunization program strategies, rotavirus vaccine is administered to children aged 24 months, with the first dose administered as soon as possible after 6 weeks of age [33, 44, 45]. Our findings highlight the need for continued surveillance and monitoring of rotavirus infection in these regions to ensure that effective prevention and control measures are maintained [38, 46].

Our results show an estimated combined prevalence of rotavirus in animals of 9.3%, highlighting the potential for zoonotic transmission to humans [6, 47], and the need for continued surveillance and control measures to reduce the burden of disease in both animal and human populations. While previous studies have estimated a high prevalence of rotavirus A in horses (51.3%) [7], our study found a much lower prevalence across all animals. However, the paucity of data from Africa makes it difficult to draw definitive conclusions about the true prevalence of rotavirus in animals in this region. Further research is needed to better understand the distribution and transmission of this virus in animals, as this information could have important implications for public health and animal welfare. In terms of the implications of rotavirus in animals, it can indeed lead to livestock death and lower household wealth, which can have significant economic impacts in areas where livestock are a primary source of income [5, 8]. Strategies for reducing rotavirus in animals could include vaccination, improved animal husbandry practices, and early detection and treatment of infections, primarily using rehydration therapy.

The estimated combined prevalence of rotavirus in environmental water sources was 31.4%. The high prevalence of rotavirus in environmental water sources suggests that contaminated water sources and sewage systems may be important in the transmission of rotavirus in Africa [12, 41], and the role that ensuring access to clean water and proper sanitation plays in the prevention and control of rotavirus infection [13, 15]. Overall, the findings underscore the importance of taking a One Health approach to the management and prevention of rotavirus infection in Africa, which considers the interconnections between human, animal, and environmental health [1, 8, 15, 47].

Our study has several limitations. First, while we identified significant differences in rotavirus prevalence between different settings, countries, and regions, we did not explore the factors underlying these differences. Further research is needed to understand the drivers of these disparities, including differences in sanitation and hygiene practices, access to health care, and animal husbandry practices. Second, our study did not analyze the molecular epidemiology of rotavirus strains circulating in Africa. This could provide important insights into the transmission dynamics of the virus across the human-animal-environment interface and help identify potential sources of infection and transmission routes. Third, our ability to detect the impact of rotavirus vaccine introduction on CFR were limited, as only 2 postvaccine-introduction studies were available. Lastly, our study identified significant residual heterogeneity that could not be fully explained by our subgroup analyses. Further research is needed to understand the sources of this heterogeneity and to develop more refined models to better estimate the prevalence of rotavirus in Africa.

This study has also several strengths. First, our study provides a comprehensive overview of rotavirus prevalence in humans, animals, and the environment in Africa, based on studies from across all African UN regions. Our meta-analysis allowed us to estimate the overall prevalence of rotavirus in different populations and settings, providing important insights into the burden of the disease in the region. Second, our study identified significant differences in rotavirus prevalence between different populations, settings, countries, and regions, highlighting the need for tailored public health interventions to address this disease. This information can help guide policy and resource allocation decisions to effectively target populations at highest risk of rotavirus infection. Finally, our study provides a foundation for future research on rotavirus in Africa, highlighting areas where further research is needed, such as understanding the drivers of differences in prevalence between populations, and investigating the molecular epidemiology of rotavirus strains circulating in the region. Overall, our study provides important insights into the epidemiology of rotavirus in Africa and lays the groundwork for future efforts to prevent and control this disease.

Supplementary Data

Supplementary materials are available at The Journal of Infectious Diseases online (http://jid.oxfordjournals.org/). Supplementary materials consist of data provided by the author that are published to benefit the reader. The posted materials are not copyedited. The contents of all supplementary data are the sole responsibility of the authors. Questions or messages regarding errors should be addressed to the author.

Notes

Financial support. This work was supported in part by the National Institutes of Health (grant number K24 AI166087 to D. T. L.); and by the Dr. Thomas D. Rees and Natalie B. Rees Presidential Endowed Chair in Global Medicine to D. T. L.