Potential Association between Zika Infection and Microcephaly during 2007 Fever Outbreak, Gabon.

Although Zika virus (ZIKV) circulates in sub-Saharan Africa, no case of ZIKV-associated microcephaly has thus far been reported. Here, we report evidence of a possible association between a 2007 outbreak of febrile illness and an increase in microcephaly and possibly ZIKV infection in Gabon.

Lower mgpB diversity in macrolide-resistant Mycoplasma genitalium infecting men visiting two sexually transmitted infection clinics in Montpellier, France.

OBJECTIVES: Men engaged in high-risk sexual behaviour, such as MSM, are likely to be infected by resistant Mycoplasma genitalium strains. Understanding the transmission dynamics is challenging. We aimed to investigate the molecular epidemiology of M. genitalium in men visiting sexually transmitted infection (STI) clinics. PATIENTS AND METHODS: Between June 2017 and February 2018, 95 M. genitalium-positive specimens from 78 men, including 76.9% MSM, visiting two STI clinics in Montpellier, France, were analysed for SNPs in the mgpB adhesin gene and number of tandem repeats in the MG_309 gene. Macrolide and fluoroquinolone resistance were determined. Typing results were compared with antibiotic resistance, sexual behaviour, sampling site, HIV pre-exposure prophylaxis (PrEP) usage and HIV status. RESULTS: Thirty-eight mgpB STs were identified, including 23 new STs, with ST4 being most prevalent. The mgpB/MG_309 typing method identified 52 genetic profiles, resulting in a discriminatory index of 0.979. Macrolide and fluoroquinolone resistance-associated mutations were detected in 58.3% and 10.8% of patients, respectively. The macrolide resistance rate was higher among MSM than among men who have sex with women only (68.4% versus 9.1%; adjusted OR, 1.57; 95% CI, 1.13-2.18; P = 0.007). A lower mgpB diversity of 0.870 was found among macrolide-resistant strains in comparison with 0.978 in macrolide-susceptible strains, with an over-representation of mgpB ST62 and ST153. CONCLUSIONS: Although macrolide resistance spread appears polyclonal in M. genitalium, the lower diversity of mgpB types among macrolide-resistant strains may reflect the easier spread of a few specific mgpB types or the occurrence of sexual networks among MSM.

Ape malaria transmission and potential for ape-to-human transfers in Africa.

Recent studies have highlighted the large diversity of malaria parasites infecting African great apes (subgenus Laverania) and their strong host specificity. Although the existence of genetic incompatibilities preventing the cross-species transfer may explain host specificity, the existence of vectors with a high preference for a determined host represents another possibility. To test this hypothesis, we undertook a 15-mo-long longitudinal entomological survey in two forest regions of Gabon, where wild apes live, at different heights under the canopy. More than 2,400 anopheline mosquitoes belonging to 18 species were collected. Among them, only three species of Anopheles were found infected with ape Plasmodium: Anopheles vinckei, Anopheles moucheti, and Anopheles marshallii Their role in transmission was confirmed by the detection of the parasites in their salivary glands. Among these species, An. vinckei showed significantly the highest prevalence of infection and was shown to be able to transmit parasites of both chimpanzees and gorillas. Transmission was also shown to be conditioned by seasonal factors and by the heights of capture under the canopy. Moreover, human landing catches of sylvan Anopheles demonstrated the propensity of these three vector species to feed on humans when available. Our results suggest therefore that the strong host specificity observed in the Laveranias is not linked to a specific association between the vertebrate host and the vector species and highlight the potential role of these vectors as bridge between apes and humans.

Malaria continues to select for sickle cell trait in Central Africa.

Sickle cell disease (SCD) is a genetic disorder that poses a serious health threat in tropical Africa, which the World Health Organization has declared a public health priority. Its persistence in human populations has been attributed to the resistance it provides to Plasmodium falciparum malaria in its heterozygous state, called sickle cell trait (SCT). Because of migration, SCT is becoming common outside tropical countries: It is now the most important genetic disorder in France, affecting one birth for every 2,400, and one of the most common in the United States. We assess the strength of the association between SCT and malaria, using current data for both SCT and malaria infections. A total of 3,959 blood samples from 195 villages distributed over the entire Republic of Gabon were analyzed. Hemoglobin variants were identified by using HPLCy (HPLC). Infections by three species of Plasmodium were detected by PCR followed by sequencing of a 201-bp fragment of cytochrome b. An increase of 10% in P. falciparum malaria prevalence is associated with an increase by 4.3% of SCT carriers. An increase of 10 y of age is associated with an increase by 5.5% of SCT carriers. Sex is not associated with SCT. These strong associations show that malaria remains a selective factor in current human populations, despite the progress of medicine and the actions undertaken to fight this disease. Our results provide evidence that evolution is still present in humans, although this is sometimes questioned by scientific, political, or religious personalities.

Genetic diversity of Plasmodium falciparum isolates from Baka Pygmies and their Bantu neighbours in the north of Gabon.

BACKGROUND: There have been many reports on the population genetic structure of Plasmodium falciparum from different endemic regions especially sub-Saharan Africa. However, few studies have been performed on neglected populations, such as the Pygmy populations. In this study, the population genetic structure of P. falciparum was investigated in the Baka Pygmies of Gabon and compared to that observed in neighboring villages composed mostly of Bantu farmers. METHODS: A total of 342 blood samples were collected from 170 Baka Pygmies and 172 Bantus in the north of Gabon (Woleu Ntem Province). Plasmodium infections were characterized by sequencing a portion of the parasite cytochrome b gene. Population genetic structure of P. falciparum in the different villages was analysed using microsatellite markers and genes coding for antigenic proteins (MSP1, MSP2, GLURP, and EBA-175). RESULTS: Overall, prevalence of P. falciparum was around 57 % and no significant difference of prevalence was observed between Pygmies and Bantus. No significant differences of population genetic structure of P. falciparum was found between Pygmy and Bantu people except for one antigen-coding gene, glurp, for which genetic data suggested the existence of a potentially disruptive selection acting on this gene in the two types of populations. The genetic structure of P. falciparum followed a pattern of isolation by distance at the scale of the study. CONCLUSION: The prevalence and genetic diversity of P. falciparum observed in Baka demonstrates a significant transmission of the parasite in this population, and some exchanges of parasites with Bantu neighbours. Despite that, some antigen-coding genes seem to have had a particular evolutionary trajectory in certain Pygmy populations due to specific local human and/or mosquito characteristics.

Diversity of malaria parasites in great apes in Gabon.

BACKGROUND: Until 2009, the Laverania subgenus counted only two representatives: Plasmodium falciparum and Plasmodium reichenowi. The recent development of non-invasive methods allowed re-exploration of plasmodial diversity in African apes. Although a large number of great ape populations have now been studied regarding Plasmodium infections in Africa, there are still vast areas of their distribution that remained unexplored. Gabon constitutes an important part of the range of western central African great ape subspecies (Pan troglodytes troglodytes and Gorilla gorilla gorilla), but has not been studied so far. In the present study, the diversity of Plasmodium species circulating in great apes in Gabon was analysed. METHODS: The analysis of 1,261 faecal samples from 791 chimpanzees and 470 gorillas collected from 24 sites all over Gabon was performed. Plasmodium infections were characterized by amplification and sequencing of a portion of the Plasmodium cytochrome b gene. RESULTS: The analysis of the 1,261 samples revealed that at least six Plasmodium species circulate in great apes in Gabon (Plasmodium praefalciparum, Plasmodium gorA (syn Plasmodium adleri), Plasmodium gorB (syn Plasmodium blacklocki) in gorillas and Plasmodium gaboni, P. reichenowi and Plasmodium billcollinsi in chimpanzees). No new phylogenetic lineages were discovered. The average infection rate was 21.3% for gorillas and 15.4% for chimpanzees. A logistic regression showed that the probability of infection was significantly dependent on the freshness of the droppings but not of the host species or of the average pluviometry of the months of collection.

Multiple independent introductions of Plasmodium falciparum in South America.

The origin of Plasmodium falciparum in South America is controversial. Some studies suggest a recent introduction during the European colonizations and the transatlantic slave trade. Other evidence--archeological and genetic--suggests a much older origin. We collected and analyzed P. falciparum isolates from different regions of the world, encompassing the distribution range of the parasite, including populations from sub-Saharan Africa, the Middle East, Southeast Asia, and South America. Analyses of microsatellite and SNP polymorphisms show that the populations of P. falciparum in South America are subdivided in two main genetic clusters (northern and southern). Phylogenetic analyses, as well as Approximate Bayesian Computation methods suggest independent introductions of the two clusters from African sources. Our estimates of divergence time between the South American populations and their likely sources favor a likely introduction from Africa during the transatlantic slave trade.

Patterns of selection on Plasmodium falciparum erythrocyte-binding antigens after the colonization of the New World.

Pathogens, which have recently colonized a new host species or new populations of the same host, are interesting models for understanding how populations may evolve in response to novel environments. During its colonization of South America from Africa, Plasmodium falciparum, the main agent of malaria, has been exposed to new conditions in distinctive new human populations (Amerindian and populations of mixed origins) that likely exerted new selective pressures on the parasite's genome. Among the genes that might have experienced strong selective pressures in response to these environmental changes, the eba genes (erythrocyte-binding antigens genes), which are involved in the invasion of the human red blood cells, constitute good candidates. In this study, we analysed, in South America, the polymorphism of three eba genes (eba-140, eba-175, eba-181) and compared it to the polymorphism observed in African populations. The aim was to determine whether these genes faced selective pressures in South America distinct from what they experienced in Africa. Patterns of genetic variability of these genes were compared to the patterns observed at two housekeeping genes (adsl and serca) and 272 SNPs to separate adaptive effects from demographic effects. We show that, conversely to Africa, eba-140 seemed to be under stronger diversifying selection in South America than eba-175. In contrast, eba-181 did not show any sign of departure from neutrality. These changes in the patterns of selection on the eba genes could be the consequence of changes in the host immune response, the host receptor polymorphisms and/or the ability of the parasite to silence or express differentially its invasion proteins.

African monkeys are infected by Plasmodium falciparum nonhuman primate-specific strains.

Recent molecular exploration of the Plasmodium species circulating in great apes in Africa has revealed the existence of a large and previously unknown diversity of Plasmodium. For instance, gorillas were found to be infected by parasites closely related to Plasmodium falciparum, suggesting that the human malignant malaria agent may have arisen after a transfer from gorillas. Although this scenario is likely in light of the data collected in great apes, it remained to be ascertained whether P. falciparum-related parasites may infect other nonhuman primates in Africa. Using molecular tools, we here explore the diversity of Plasmodium species infecting monkeys in Central Africa. In addition to previously described Hepatocystis and Plasmodium species (Plasmodium gonderi and Plasmodium sp DAJ-2004), we have found one African monkey to be infected by a P. falciparum-related parasite. Examination of the nuclear and mitochondrial genomes of this parasite reveals that it is specific of nonhuman primates, indicating that P. falciparum-related pathogens can naturally circulate in some monkey populations in Africa. We also show that at least two distinct genetic entities of P. falciparum infect nonhuman primates and humans, respectively. Our discoveries bring into question the proposed gorilla origin of human P. falciparum.

Antimicrobial-Resistant Bacteria Carriage in Rodents According to Habitat Anthropization.

It is increasingly suggested that the dynamics of antimicrobial-resistant bacteria in the wild are mostly anthropogenically driven, but the spatial and temporal scales at which these phenomena occur in landscapes are only partially understood. Here, we explore this topic by studying antimicrobial resistance in the commensal bacteria from micromammals sampled at 12 sites from a large heterogenous landscape (the Carmargue area, Rhone Delta) along a gradient of anthropization: natural reserves, rural areas, towns, and sewage-water treatment plants. There was a positive relationship between the frequency of antimicrobial-resistant bacteria and the level of habitat anthropization. Although low, antimicrobial resistance was also present in natural reserves, even in the oldest one, founded in 1954. This study is one of the first to support the idea that rodents in human-altered habitats are important components of the environmental pool of resistance to clinically relevant antimicrobials and also that a "One Health" approach is required to assess issues related to antimicrobial resistance dynamics in anthropized landscapes.

Burden of hepatitis B virus infection in pregnant women attending antenatal clinics in the southern Gabon.

Objectives: Hepatitis B virus (HBV) infection remains a public health threat in middle- and low-income countries, where mother-to-child transmission plays an important role. The aim of this study was to assess the burden of this infection among pregnant women in southern Gabon and the risk of vertical transmission. Methods: The study was a prospective investigation conducted from April 2021 to January 2022. Study participants were pregnant women aged 18 and over attending antenatal clinics in Franceville. Blood samples were collected to test for HBV surface antigen, anti-hepatitis B core, hepatitis B e antigen, and anti-hepatitis B e markers and to assess HBV infection. Results: We recruited 901 women with a median age of 26 years (interquartile range: 21-32). Overall prevalence of infection was 3.9% (confidence interval: 2.7-5.4%). 418/901 or 46.4% were anti-hepatitis B core positive. Among HBV surface antigen-positive women, 1/35 were hepatitis B e antigen-positive with a viral load >200,000 IU/ml. Over 64% of participants had no information about HBV infection, and none knew that the virus could be transmitted from mother to child. Conclusions: This study reveals a low HBV prevalence in pregnant women in Gabon and a low risk of vertical transmission of the virus. However, the rate of exposure of the population to the virus remains high and calls for improving actions and interventions for potential elimination goals.

Incidence of adult brain cancers is higher in countries where the protozoan parasite Toxoplasma gondii is common.

We explored associations between the common protozoan parasite Toxoplasma gondii and brain cancers in human populations. We predicted that T. gondii could increase the risk of brain cancer because it is a long-lived parasite that encysts in the brain, where it provokes inflammation and inhibits apoptosis. We used a medical geography approach based on the national incidence of brain cancers and seroprevalence of T. gondii. We corrected reports of incidence for national gross domestic product because wealth probably increases the ability to detect cancer. We also included gender, cell phone use and latitude as variables in our initial models. Prevalence of T. gondii explained 19 per cent of the residual variance in brain cancer incidence after controlling for the positive effects of gross domestic product and latitude among nations. Infection with T. gondii was associated with a 1.8-fold increase in the risk of brain cancers across the range of T. gondii prevalence in our dataset (4-67%). These results, though correlational, suggest that T. gondii should be investigated further as a possible oncogenic pathogen of humans.

Molecular Typing Reveals Distinct Mycoplasma genitalium Transmission Networks among a Cohort of Men Who Have Sex with Men and a Cohort of Women in France.

Mycoplasma genitalium causes sexually transmitted infecti.ons in men and women. Treatment failures to macrolides and fluoroquinolones have been reported worldwide. Although the mgpB typing method has often been used in M. genitalium-infected men who have sex with men (MSM), limited typing data are available for M. genitalium-infected women. In this study, we aimed to investigate the genetic relationship between M. genitalium strains and their antibiotic resistance profile in a cohort of MSM (86.2% on HIV preexposure prophylaxis [PrEP], 13.8% HIV positive) and a large cohort of women using mgpB/MG309 typing. The mgpB types were determined in 374 samples from 305 women and 65 MSM. Three MSM and one woman had two concurrent or subsequent samples. Macrolide and fluoroquinolone resistance-associated mutations were searched in the 23S rRNA as well as parC and gyrA genes. The mgpB phylogenetic construction revealed three large clusters that differed according to sexual practices and geographical origin of patients. The prevalence of macrolide and fluoroquinolone resistance was significantly higher in MSM compared with women (95.4% vs. 14.1% and 30.6% vs. 7.2%, p < 0.001, respectively). The macrolide resistance spread was polyclonal in both populations, but clonal diffusion of two dual-resistant types was observed in PrEP users in association with high antibiotic pressure and dense connectivity in this population.

Multiresistant Enterobacteriaceae in yellow-legged gull chicks in their first weeks of life.

Wild animal species living in anthropogenic areas are commonly carriers of antimicrobial-resistant bacteria (AMRB), but their role in the epidemiology of these bacteria is unclear. Several studies on AMRB in wildlife have been cross-sectional in design and sampled individual animals at only one point in time. To further understand the role of wildlife in maintaining and potentially transmitting these bacteria to humans and livestock, longitudinal studies are needed in which samples are collected from individual animals over multiple time periods. In Europe, free-ranging yellow-legged gulls (Larus michahellis) commonly live in industrialized areas, forage in landfills, and have been found to carry AMRB in their feces. Using bacterial metagenomics and antimicrobial resistance characterization, we investigated the spatial and temporal patterns of AMRB in a nesting colony of yellow-legged gulls from an industrialized area in southern France. We collected 54 cloacal swabs from 31 yellow-legged gull chicks in 20 nests on three dates in 2016. We found that AMRB in chicks increased over time and was not spatially structured within the gull colony. This study highlights the complex occurrence of AMRB in a free-ranging wildlife species and contributes to our understanding of the public health risks and implications associated with ARMB-carrying gulls living in anthropogenic areas.

Prevalence of SARS-CoV-2 antibodies in the Republic of Congo in mid-2021.

Objectives: To estimate the seroprevalence of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) antibodies in the general population in the Republic of Congo. Methods: In this cross-sectional study, conducted from June to July 2021, participants were recruited from the general population in three districts in the Republic of Congo. Eligible participants were tested for anti-SARS-CoV-2 antibodies using a rapid diagnostic assay. Results: Overall, 31.8% [95% confidence interval (CI) 29.5-34.0] of the 1669 participants tested positive for anti-SARS-CoV-2 antibodies. Higher prevalence was observed in the rural region (37.3%, 95% CI 31.0-44.1%) than the urban region (30.9%, 95% CI 28.5-33.3); however, the difference was not significant. The risk of testing positive for anti-SARS-CoV-2 antibodies increased significantly with age, ranging from 22.5% (95% CI 18.1-27.5) in 15-24 year olds to 47.9% (95% CI 39.3-56.5) in 55-64 year olds. Conclusions: The antibody levels observed in this survey correlate with a moderate rate of virus circulation, which correlates with the low number of confirmed cases of coronavirus disease 2019 in the Republic of Congo.

Trend of expansion of SARS-CoV-2 infection and COVID-19 burden in Gabon (Central Africa) in mid-2021, based on a serological survey.

Objective: To estimate the seroprevalence of anti-SARS-CoV-2 antibodies in the general population in Gabon, Central Africa. Methods: From May to July 2021, a cross-sectional study involving participants recruited in the general population in three districts in Gabon was conducted. Eligible participants who provided written informed consent were tested for anti-SARS-CoV-2 antibodies using a simple rapid diagnostic assay. Results: Overall, 1609 participants were recruited, 1361 (84.6%) from urban sites and 248 (15.4%) from a rural area. The estimated overall seroprevalence was 13.1% (95% CI 11.4-14.8%). The risk of seropositivity increased with age, and the prevalence in the different age groups ranged from 12.9% (8.0-19.4%) in those aged 15-24 years to 23.3% (14.2-34.6%) in those ≥ 65 years old. A higher prevalence was found in the rural population (17.3%; 12.8-22.6%) compared with urban regions (12.3%; 10.6-14.1%). Being a woman was also associated with higher risk of infection (p < 0.001). Conclusions: This seroprevalence survey revealed a moderate seroprevalence in Gabon, illustrating a relatively low rate of circulation of the virus in the country and correlating with low numbers of confirmed cases and deaths reported to date.

The cost of a bodyguard.

Host manipulation by parasites not only captures the imagination but has important epidemiological implications. The conventional view is that parasites face a trade-off between the benefits of host manipulation and their costs to fitness-related traits, such as longevity and fecundity. However, this trade-off hypothesis remains to be tested. Dinocampus coccinellae is a common parasitic wasp of the spotted lady beetle Coleomegilla maculata. Females deposit a single egg in the haemocoel of the host, and during larval development the parasitoid feeds on host tissues. At the prepupal stage, the parasitoid egresses from its host by forcing its way through the coccinellid's abdominal segments and begins spinning a cocoon between the ladybird's legs. Remarkably, D. coccinellae does not kill its host during its development, an atypical feature for parasitoids. We first showed under laboratory conditions that parasitoid cocoons that were attended by a living and manipulated ladybird suffered less predation than did cocoons alone or cocoons under dead ladybirds. We then demonstrated that the length of the manipulation period is negatively correlated with parasitoid fecundity but not with longevity. In addition to documenting an original case of bodyguard manipulation, our study provides the first evidence of a cost required for manipulating host behaviour.

Serological biomarker for assessing human exposure to Aedes mosquito bites during a randomized vector control intervention trial in northeastern Thailand.

BACKGROUND: Aedes mosquitoes are vectors for several major arboviruses of public health concern including dengue viruses. The relationships between Aedes infestation and disease transmission are complex wherein the epidemiological dynamics can be difficult to discern because of a lack of robust and sensitive indicators for predicting transmission risk. This study investigates the use of anti-Aedes saliva antibodies as a serological biomarker for Aedes mosquito bites to assess small scale variations in adult Aedes density and dengue virus (DENV) transmission risk in northeastern Thailand. Individual characteristics, behaviors/occupation and socio-demographics, climatic and epidemiological risk factors associated with human-mosquito exposure are also addressed. METHODS: The study was conducted within a randomized clustered control trial in Roi Et and Khon Kaen provinces over a consecutive 19 months period. Thirty-six (36) clusters were selected, each of ten houses. Serological and entomological surveys were conducted in all houses every four months and monthly in three sentinel households per cluster between September 2017 and April 2019 for blood spot collections and recording concurrent immature and adult Aedes indices. Additionally, the human exposure to Aedes mosquito bites (i.e., Mosquito Exposure Index or MEI) was estimated by ELISA measuring levels of human antibody response to the specific Nterm-34 kDa salivary antigen. The relationships between the MEI, vector infestation indices (adult and immature stages) and vector DENV infection were evaluated using a two-level (house and individual levels) mixed model analysis with one-month lag autoregressive correlation. RESULTS: There was a strong positive relationship between the MEI and adult Aedes (indoor and outdoor) density. Individuals from households with a medium mosquito density (mean difference: 0.091, p<0.001) and households with a high mosquito density (mean difference: 0.131, p<0.001) had higher MEI's compared to individuals from households without Aedes. On a similar trend, individuals from households with a low, medium or high indoor Aedes densities (mean difference: 0.021, p<0.007, 0.053, p<0.0001 and 0.037, p<0.0001 for low, medium and high levels of infestation, respectively) had higher MEI than individuals from houses without indoor Aedes. The MEI was driven by individual characteristics, such as gender, age and occupation/behaviors, and varied according to climatic, seasonal factors and vector control intervention (p<0.05). Nevertheless, the study did not demonstrate a clear correlation between MEI and the presence of DENV-infected Aedes. CONCLUSION: This study represents an important step toward the validation of the specific IgG response to the Aedes salivary peptide Nterm-34kDa as a proxy measure for Aedes infestation levels and human-mosquito exposure risk in a dengue endemic setting. The use of the IgG response to the Nterm-34 kDa peptide as a viable diagnostic tool for estimating dengue transmission requires further investigations and validation in other geographical and transmission settings.

High prevalence of SARS-CoV-2 antibodies in pets from COVID-19+ households.

In a survey of household cats and dogs of laboratory-confirmed COVID-19 patients, we found a high seroprevalence of SARS-CoV-2 antibodies, ranging from 21% to 53%, depending on the positivity criteria chosen. Seropositivity was significantly greater among pets from COVID-19+ households compared to those with owners of unknown status. Our results highlight the potential role of pets in the spread of the epidemic.

Avian influenza circulation in the Camargue (south of France) during the 2006-07 season.

Situated at the crossroads of numerous migratory routes of Palaearctic birds, the Camargue is considered a high-risk area for the introduction and transmission of numerous avian-borne pathogens. We investigated the epidemiologic cycles of avian influenza viruses (AIVs) in the local bird community by performing regular sampling on a large variety of bird species during 11 consecutive months in 2006-07. To detect the presence of AIV, SYBR green reverse transcriptase-PCR targeting the M gene was performed on 2901 samples from 66 bird species. A clear seasonal pattern of AIV circulation in ducks was observed during autumn and winter, with higher prevalence rates in early fall. Our results also support an absence of circulation of AIV in passerine birds during spring and the wintering periods. Finally, even if the prevalence of infection was very low, AIVs were found in gulls in breeding colonies, indicating a possible specific circulation in spring in these birds.