Pierre Roques

The recent resurgence of measles during the post-COVID-19 period represents a major public health concern worldwide, particularly for low- and middle-income countries like Guinea which has experienced recurrent measles epidemics in recent years, characterized by limited clinical surveillance. In this context, environmental surveillance adapted to the constraints of decentralized wastewater management can represent an effective and cost-efficient tool for monitoring measles virus circulation. Following a pilot study conducted in the semi-enclosed wastewater drainage networks of the city center of Conakry (March 2022–April 2024), measles surveillance was expanded to the entire city, including informal networks and natural waterways. From August 2024 to October 2025, measles virus was detected in 32% of the wastewater samples analyzed (345/1072) with a clear peak during the early 2025 epidemic. This detection consistent with national clinical surveillance data demonstrates the value of wastewater monitoring as an early warning tool, helping to anticipate the resurgence of measles cases in the population. The quantification of the measles virus was normalized relative to the crAssphage signal, a quantitative indicator of the density of the populations being monitored. The modeling of our environmental surveillance adapted to a decentralized surveillance framework proposes an accurate characterization of the spatiotemporal dynamics of measles virus circulation in municipalities of Conakry and allows early alert about outbreaks before detection in health centers. This work demonstrates the feasibility of environmental surveillance in low-resource country settings and proves that it is a relevant tool during epidemic periods, helping to complement and strengthen the national surveillance system.

Background and Aim: Hepatitis E virus (HEV) is an important cause of acute viral hepatitis worldwide and remains a neglected public health concern in sub-Saharan Africa. Although several African studies have reported HEV circulation, no comprehensive synthesis has integrated human, animal, and environmental evidence from West Africa. This study aimed to determine the prevalence, geographic distribution, risk-group characteristics, and genotype diversity of HEV in West Africa using a One Health approach. Materials and Methods: A systematic review and meta-analysis was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and registered in PROSPERO (CRD420251178069). PubMed, ScienceDirect, Google Scholar, and reference lists were searched for studies published between 1997 and August 2025. Studies involving humans, animals, and environmental samples from West African countries were included. Data extraction and quality assessment were performed independently by two reviewers. A random-effects meta-analysis using Comprehensive Meta-Analysis software version 3.0 was conducted to estimate the pooled prevalence and investigate heterogeneity. Human populations were stratified into low- and high-risk groups according to exposure characteristics. Results: Ninety-six eligible studies conducted in 12 countries and involving 36,014 individuals were included. A total of 9,465 HEV-positive cases were identified. The pooled overall seroprevalence was 9.7% (95% confidence interval [CI]: 8.2%–11.5%), with substantial heterogeneity (I² = 97.53%). The pooled prevalence of anti-HEV immunoglobulin (Ig)G was 15.7%, ranging from 2.7% in Guinea to 29.3% in Burkina Faso. High-risk populations exhibited higher prevalences of IgG (25.9%), IgM (4.6%), and total antibodies (16.9%) than low-risk groups. Animal reservoirs, particularly pigs, showed high infection frequencies, whereas environmental contamination reached 24% in vegetables. Human genotypes 1e, 2b, 3e, 3f, and 4b, and animal- and environment-associated genotypes 3a and 3c were identified across the region. Conclusion: HEV infection is widely distributed in West Africa, with marked differences among countries and population groups. The coexistence of human, animal, and environmental reservoirs highlights the importance of integrated One Health surveillance and targeted prevention strategies to reduce the regional burden of HEV infection. Keywords: environmental contamination, genotype distribution, hepatitis E virus, meta-analysis, One Health, prevalence, systematic review, West Africa.

Background: The recent resurgence of measles during the post-COVID-19 period represents a major public health concern worldwide, particularly for low- and middle-income countries (LMIC) like Guinea which has experienced recurrent measles epidemics, characterized by limited clinical surveillance. In this context, our study aimed to use environmental surveillance of wastewater to provide an effective and cost-efficient tool for monitoring measles virus circulation.Methods: In the absence of wastewater treatment plants in Guinea, our study was conducted in the semi-enclosed wastewater drainage networks, informal drainage networks and natural waterways. Measles virus detection in wastewater was performed using a simple, low-cost protocol adapted to LMIC. Measles quantification was normalized relative to the crAssphage signal, a quantitative indicator of the populations being monitored.Results: From August 2024 to October 2025, measles virus was detected in 32% of the wastewater samples analyzed (345/1072) with a clear peak during the early 2025 epidemic. This detection consistent with national clinical surveillance data demonstrates the value of wastewater monitoring as an early warning tool, helping to anticipate the resurgence of measles cases in the population.Interpretation: The modeling of our environmental surveillance adapted to a decentralized surveillance framework proposes an accurate characterization of the spatiotemporal dynamics of measles virus circulation in municipalities of Conakry and allows early alert about outbreaks before detection in health centers. This work demonstrates the feasibility of environmental surveillance in low-resource country settings and proves that it is a relevant tool during epidemic periods, helping to complement and strengthen the national surveillance system.

Hepatitis E virus (HEV) is a major cause of acute viral hepatitis worldwide, with zoonotic genotypes detected in humans and animals. In Africa, limited data exist on environmental HEV circulation. Here, we report the first detection of Rocahepevirus ratti (RHEV) in urban wastewater from Conakry, Guinea. From December 2024 to April 2025, Rocahepevirus ratti (RHEV) has been detected in 35 out of 180 urban untreated wastewater samples in Conakry, Guinea. The phylogenetic analysis of partial HEV ORF1 genome segments reveals clustering with African rodent RHEV strains, highlighting environmental contamination and potential zoonotic risk for human populations in proximity. This finding underscores the need for integrated One Health surveillance to monitor HEV transmission at the human–animal–environment interface in West Africa, particularly in Guinea.

Hepatitis E virus (HEV) is a major cause of acute viral hepatitis worldwide, with zoonotic genotypes detected in humans and animals. In Africa, limited data exist on environmental HEV circulation. Here, we report the first detection of Rocahepevirus ratti (RHEV) in urban wastewater from Conakry, Guinea. From December 2024 to April 2025, Rocahepevirus ratti (RHEV) has been detected in 35 out of 180 urban untreated wastewater samples in Conakry, Guinea. Phylogenetic analysis of partial HEV ORF1 genome segments reveals clustering with African rodents RHEV strains, highlighting environmental contamination and potential zoonotic risk for human population in proximity. This finding underscores the need for integrated One Health surveillance to monitor HEV transmission at the human-animal-environment interface in West Africa particularly in Guinea.

Chikungunya virus (CHIKV) induces predominantly symptomatic infections, marked by fever, myalgia, rash and polyarthralgia that can last for up to 3 years after infection. Understanding the pathophysiology of CHIKV in the joints is challenging due to limited access to biological samples. Using a reporter virus expressing Nanoluciferase in a mouse model allowed us to monitor viral replication in real-time during acute and postacute phases. We showed viral replication in chondrocyte containing tissue in the metatarsi joints and confirmed with ex vivo analyses viral replication in leg bones and articular cartilages with histological evidence of focal erosive lesions and periarticular inflammation. Moreover, human chondrocytes prove susceptible to CHIKV infection, exhibiting viral production and bioluminescence activity. CHIKV induced apoptosis, the up-regulation of markers associated with cartilage remodeling and altered cytokine production. Our study provides insights into the ability of CHIKV to infect articular cartilages, shedding light on the mechanisms of alphaviral arthritis.

Chikungunya virus (CHIKV) is an alphavirus transmitted by mosquitos that poses a threat to global public health and for which there is an urgent need for widespread access to globally licensed vaccines. Here, we demonstrate that an inactivated CHIKV vaccine (BBV87) protects against systemic infection with CHIKV in a non-human primate (NHP) challenge model. Groups of five cynomolgus macaques received two doses of 20 µg BBV87 vaccine or saline alone (28 days apart). Twenty-eight days after the second immunisation, all animals were challenged with CHIKV. All controls were productively infected with detectable viremia and pathological responses following challenge, including altered thermoregulation, haematological and cytokine changes. Critically, the histopathological analysis of finger joints identified areas of inflammation in the synovium. By contrast vaccinated macaques had no detectable viremia and none of the pathological changes were reported in control animals. This study demonstrates that a 20 µg dose of BBV87 vaccine confers robust protection in vivo, both on the acquisition of infection and pathology.

The Journal of Public Health in Africa (JPHiA) is a peer-reviewed, academic journal that focuses on health issues in the African continent. The journal editors seek high quality original articles on public health related issues, reviews, comments and more. The aim of the journal is to move public health discourse from the background to the forefront. The success of Africa’s struggle against disease depends on public health approaches.

Early pregnancy Zika virus (ZIKV) infection is associated with major brain damage in fetuses, leading to microcephaly in 0.6–5.0% of cases, but the underlying mechanisms remain largely unknown. To understand the kinetics of ZIKV infection during fetal development in a nonhuman primate model, four cynomolgus macaque fetuses were exposed in utero through echo-guided intramuscular inoculation with 103 PFU of ZIKV at 70–80 days of gestation, 2 controls were mock inoculated. Clinical, immuno-virological and ultrasound imaging follow-ups of the mother/fetus pairs were performed until autopsy after cesarean section 1 or 2 months after exposure (n = 3 per group). ZIKV was transmitted from the fetus to the mother and then replicate in the peripheral blood of the mother from week 1 to 4 postexposure. Infected fetal brains tended to be smaller than those of controls, but not the femur lengths. High level of viral RNA ws found after the first month in brain tissues and placenta. Thereafter, there was partial control of the virus in the fetus, resulting in a decreased number of infected tissue sections and a decreased viral load. Immune cellular and humoral responses were effectively induced. ZIKV infection during the second trimester of gestation induces short-term brain injury, and although viral genomes persist in tissues, most of the virus is cleared before delivery.

Salmonella is one of the world’s leading causes of zoonotic and foodborne illnesses. Recently, antimicrobial resistance (AMR) has become one of the most critical challenges to public health and food safety. Herein, we employed a meta-analysis to determine the pooled prevalence and spatiotemporal distribution of serovars and antimicrobial resistance in NTS in Burkina Faso. To find eligible articles, a comprehensive literature search of PubMed, African Journals Online, ScienceDirect, Google Scholar, and the gray literature (university libraries) in Burkina was conducted for the period from 2008 to 2020. Studies meeting the inclusion criteria were selected and assessed for risk of bias. To assess the temporal and spatial relationships between serotypes and resistant strains from humans, animals, food, and the environment, a random-effects statistical model meta-analysis was carried out using the Comprehensive Meta-Analysis Version 3.0 program. The NTS prevalence rates were 4.6% (95% CI: 3–7) and 20.1% (95% CI: 6.6–47.4) in humans and animals, respectively, and 16.8% (95% CI: 10.5–25.8) and 15.6% (95% CI: 8.2–27.5) in food and the environment, respectively. Most NTS serovars were S. Derby, reported both in food and animals, and S. Typhimurium, reported in humans, while S. Croft II, S. Jodpur II, and S. Kentucky were the most prevalent in the environment. NTS isolates were highly resistant to erythromycin, amoxicillin, cefixime, and cephalothin, with a pooled prevalence of multidrug resistance of 29% (95% CI: 14.5–49.5). The results of this review show a high diversity of Salmonella serotypes, as well as high antibiotic resistance in Salmonella isolates from animal, human, food, and environmental samples in Burkina, calling for a consolidated “One Health” approach to better understand the drivers of pathogen emergence, spread, and antimicrobial resistance, as well as the formulation of intervention measures needed to limit the risk associated with the disease.