Search

Monkeypox virus (MPXV) is an emerging zoonotic Orthopoxvirus causing mpox in humans, a disease similar to the eradicated smallpox (1). Since identification in a monkey in 1958 (2) and a [...]

BackgroundFebrile jaundice is a common indicator of certain infectious diseases, including hepatitis E. In Cameroon, the yellow fever virus is the only pathogen that is monitored in patients who present with this symptom. However, more than 90% of the samples received as part of this surveillance are negative for yellow fever. This study aimed to describe the prevalence and hepatitis E virus (HEV) genotype among yellow fever-negative patients in the Far North and West regions of Cameroon.MethodsIn a cross-sectional study, yellow fever surveillance-negative samples collected between January 2021 and January 2023 were retrospectively analyzed. Anti-HEV IgM and IgG antibodies were tested using commercially available ELISA kits. Anti-HEV IgM and/or IgG positive samples were tested for HEV RNA by real-time RT-PCR, followed by nested RT-PCR, sequencing and phylogenetic analysis.ResultsOverall, 121 of the 543 samples (22.3%, 95% CI: 19.0% - 26.0%) were positive for at least one anti-HEV marker. Amongst these, 8.1% (44/543) were positive for anti-HEV IgM, 5.9% (32/543) for anti-HEV IgG, and 8.3% (45/544) for both markers. A total of 15.2% (12/79) samples were positive for HEV RNA real-time RT-PCR and 8 samples were positive for HEV RNA by nested RT-PCR. Phylogenetic analysis showed that the retrieved sequences clustered within HEV genotypes/subtypes 1/1e, 3/3f and 4/4b.ConclusionOur results showed that HEV is one of the causes of acute febrile jaundice in patients enrolled in the yellow fever surveillance program in two regions of Cameroon. We described the circulation of three HEV genotypes, including two zoonotic genotypes. Further studies will be important to elucidate the transmission routes of these zoonotic HEV genotypes to humans in Cameroon.

To the Editor: Circulation of new arboviruses of the genus Flavivirus poses a major problem for differential diagnosis. Zika virus, a mosquitoborne virus of the family Flaviviridae, is closely related [...]

Because the number of reported cases of yellow fever has increased over the past 2 decades, it is considered a reemerging disease (1,2). The World Health Organization (WHO) requires that [...]

We review here the epidemiological studies performed by our group on human retrovirus HTLV-I and HTLV-II infections and the associated diseases in French Guiana since 1984. French Guiana is an overseas French administrative district located between Brazil and Surinam. Its population is characterized by a large variety of ethnic groups, including several populations of African origin and various populations of Amerindian origin. Several epidemiological studies of large samples of pregnant women and in remote villages showed that HTLV-I is highly endemic in this area but is restricted to groups of African origin, especially the Noir-Marrons. In this endemic population, the results of segregation analysis in a genetic epidemiological study were consistent with the presence of a dominant major gene predisposing to HTLV-I infection, especially in children. In contrast, HTLV-II infection appears to be rare in French Guiana, having been found in only a few individuals of Brazilian origin. From a molecular point of view, the HTLV-I strains present in the Noir-Marrons, Creoles and Amerindians appear to originate from Africa, as they belong to the large cosmopolitan molecular subtype A.

In April 2009, a pandemic strain of influenza A (H1N1) (pH1N1) virus emerged in Mexico and the United States; the World Health Organization declared a pandemic alert on June 11, [...]

A serologic survey for Mayaro virus (Alphavirus, Togaviridae) in 28 wild nonflying forest mammal species in French Guiana showed a prevalence ranging from 0% to 52% and increasing with age. [...]

To the Editor: Hepatitis E virus (HEV) is endemic to India (1,2) and Central African Republic (3,4), although different strains circulate in the countries. In May 2011, a case of [...]

Abstract Background Hepatitis E virus (HEV), an enterically transmitted pathogen, is highly endemic in several African countries. Pregnant women are at particularly high risk for acute or severe hepatitis E. In Gabon, a central African country, the prevalence of antibodies to HEV among pregnant women is 14.1%. Recent studies have demonstrated unusual patterns of hepatitis E (chronic hepatitis, cirrhosis) among immunodeficient patients. Findings We investigated the prevalence of antibodies to HEV among pregnant women infected with HIV-1 or HTLV-1 in Gabon. Of 243 samples collected, 183 were positive for HIV-1 and 60 for HTLV-1; 16 women (6.6%) had IgG antibodies to HEV. The seroprevalence was higher among HIV-1-infected women (7.1%) than HTLV-1-infected women (5.0%). Moreover, the HIV-1 viral load was significantly increased (p ≤ 0.02) among women with past-HEV exposure (1.3E+05 vs 5.7E+04 copies per ml), whereas no difference was found in HTLV-1 proviral load (9.0E+01 vs 1.1E+03 copies per ml). Conclusions These data provide evidence that HIV-1-infected women are at risk for acute or severe infection if they are exposed to HEV during pregnancy, with an increased viral load.

Abstract Background The causative agent of yellow fever is an arbovirus of the Flaviviridae family transmitted by infected Aedes mosquitoes, particularly in Africa. In the Central African Republic since 2006, cases have been notified in the provinces of Ombella-Mpoko, Ouham-Pende, Basse-Kotto, Haute-Kotto and in Bangui the capital. As the presence of a vector of yellow fever virus (YFV) represents a risk for spread of the disease, we undertook entomological investigations at these sites to identify potential vectors of YFV and their abundance. Findings Between 2006 and 2010, 5066 mosquitoes belonging to six genera and 43 species were identified. The 20 species of the Aedes genus identified included Ae. aegypti, the main vector of YFV in urban settings, and species found in tropical forests, such as Ae. africanus, Ae. simpsoni, Ae. luteocephalus, Ae. vittatus and Ae. opok. These species were not distributed uniformly in the various sites studied. Thus, the predominant Aedes species was Ae. aegypti in Bangui (90.7 %) and Basse-Kotto (42.2 %), Ae. africanus in Ombella-Mpoko (67.4 %) and Haute-Kotto (77.8 %) and Ae. vittatus in Ouham-Pende (62.2 %). Ae. albopictus was also found in Bangui. The distribution of these dominant species differed significantly according to study site (P Aedes mosquitoes analysed by polymerase chain reaction contained the YFV genome. Conclusion The results indicate a wide diversity of vector species for YFV in the Central African Republic. The establishment of surveillance and vector control programs should take into account the ecological specificity of each species.

Abstract Background In Africa, the wide genetic diversity of HIV has resulted in emergence of new strains, rapid spread of this virus in sub-Saharan populations and therefore spread of the HIV epidemic throughout the continent. Methods To determine the prevalence of antibodies to HIV among a high-risk population in Gabon, 1098 and 2916 samples were collected from pregnant women in 2005 and 2008, respectively. HIV genotypes were evaluated in 107 HIV-1-positive samples to determine the circulating subtypes of strains and their resistance to antiretroviral drugs (ARVs). Results The seroprevalences were 6.3% in 2005 and 6.0% in 2008. The main subtype was recombinant CRF02_AG (46.7%), followed by the subtypes A (19.6%), G (10.3%), F (4.7%), H (1.9%) and D (0.9%) and the complex recombinants CRF06_cpx (1.9%) and CRF11_cpx (1.9%); 12.1% of subtypes could not be characterized. Analysis of ARVs resistance to the protease and reverse transcriptase coding regions showed mutations associated with extensive subtype polymorphism. In the present study, the HIV strains showed reduced susceptibility to ARVs (2.8%), particularly to protease inhibitors (1.9%) and nucleoside reverse transcriptase inhibitors (0.9%). Conclusions The evolving genetic diversity of HIV calls for continuous monitoring of its molecular epidemiology in Gabon and in other central African countries.

Abstract Background Each of the pathogenic human retroviruses (HIV-1/2 and HTLV-1) has a nonhuman primate counterpart, and the presence of these retroviruses in humans results from interspecies transmission. The passage of another simian retrovirus, simian foamy virus (SFV), from apes or monkeys to humans has been reported. Mandrillus sphinx, a monkey species living in central Africa, is naturally infected with SFV. We evaluated the natural history of the virus in a free-ranging colony of mandrills and investigated possible transmission of mandrill SFV to humans. Results We studied 84 semi-free-ranging captive mandrills at the Primate Centre of the Centre International de Recherches Médicales de Franceville (Gabon) and 15 wild mandrills caught in various areas of the country. The presence of SFV was also evaluated in 20 people who worked closely with mandrills and other nonhuman primates. SFV infection was determined by specific serological (Western blot) and molecular (nested PCR of the integrase region in the polymerase gene) assays. Seropositivity for SFV was found in 70/84 (83%) captive and 9/15 (60%) wild-caught mandrills and in 2/20 (10%) humans. The 425-bp SFV integrase fragment was detected in peripheral blood DNA from 53 captive and 8 wild-caught mandrills and in two personnel. Sequence and phylogenetic studies demonstrated the presence of two distinct strains of mandrill SFV, one clade including SFVs from mandrills living in the northern part of Gabon and the second consisting of SFV from animals living in the south. One man who had been bitten 10 years earlier by a mandrill and another bitten 22 years earlier by a macaque were found to be SFV infected, both at the Primate Centre. The second man had a sequence close to SFVmac sequences. Comparative sequence analysis of the virus from the first man and from the mandrill showed nearly identical sequences, indicating genetic stability of SFV over time. Conclusion Our results show a high prevalence of SFV infection in a semi-free-ranging colony of mandrills, with the presence of two different strains. We also showed transmission of SFV from a mandrill and a macaque to humans.

Abstract Hepatitis E virus (HEV) is highly endemic in several African countries with high mortality rate among pregnant women. Nothing is known about the circulation of this virus in central Africa. We evaluated therefore the prevalence of anti-HEV IgG in samples collected from pregnant women living in the five main cities of Gabon, central Africa. We found that 14.1% (119/840) of pregnant women had anti-HEV IgG. The prevalence differed between regions and between age groups. In 391 newly collected samples from the region where the highest prevalence was found, a significant difference (p < 0.05) in seroprevalence was found between rural (6.4%) and urban (13.5%) areas. These data provide evidence of a high prevalence of HEV in Gabon, providing indirect evidence of past contact with this virus.