Serological Survey Research Articles

Avian influenza overview September-December 2023.

Between 2 September and 1 December 2023, highly pathogenic avian influenza (HPAI) A(H5) outbreaks were reported in domestic (88) and wild (175) birds across 23 countries in Europe. Compared to previous years, the increase in the number of HPAI virus detections in waterfowl has been delayed, possibly due to a later start of the autumn migration of several wild bird species. Common cranes were the most frequently affected species during this reporting period with mortality events being described in several European countries. Most HPAI outbreaks reported in poultry were primary outbreaks following the introduction of the virus by wild birds, with the exception of Hungary, where two clusters involving secondary spread occurred. HPAI viruses identified in Europe belonged to eleven different genotypes, seven of which were new. With regard to mammals, the serological survey conducted in all fur farms in Finland revealed 29 additional serologically positive farms during this reporting period. Wild mammals continued to be affected mostly in the Americas, from where further spread into wild birds and mammals in the Antarctic region was described for the first time. Since the last report and as of 1 December 2023, three fatal and one severe human A(H5N1) infection with clade 2.3.2.1c viruses have been reported by Cambodia, and one A(H9N2) infection was reported from China. No human infections related to the avian influenza detections in animals in fur farms in Finland have been reported, and human infections with avian influenza remain a rare event. The risk of infection with currently circulating avian H5 influenza viruses of clade 2.3.4.4b in Europe remains low for the general population in the EU/EEA. The risk of infection remains low to moderate for occupationally or otherwise exposed people to infected birds or mammals (wild or domesticated); this assessment covers different situations that depend on the level of exposure.

Serological Survey for Three Canine Viruses in Brazilian Wild Carnivores : Antibodies Against Canine Viruses in Wild Carnivores.

We evaluated the presence of antibodies against CaHV-1, CDV, and CPV-2 in serum samples from Brazilian wild carnivore species. Nine maned wolves and six crab-eating foxes were tested for CaHV-1 and CDV by virus neutralization test and CPV-2 by hemagglutination inhibition assay. Antibodies to CaHV-1, CDV, and CPV-2 were detected in serum samples of 1 (6.7%), 5 (33.3%), and 10 (66.7%) wild carnivores, respectively. Two maned wolves and one crab-eating fox were seropositive simultaneously for CDV and CPV-2. Antibodies against all viruses were detected in one crab-eating fox. This is the first report of CaHV-1 antibody detection in crab-eating foxes.

Seroprevalence and Molecular Characterization of Brucella abortus from the Himalayan Marmot in Qinghai, China.

Brucellosis is a serious public health issue in Qinghai (QH), China. Surveying the seroprevalence and isolation of B. abortus strains from marmots is key to understanding the role of wildlife in the maintenance and spread of brucellosis. In this study, a set of methods, including a serology survey, bacteriology, antibiotic susceptibility, molecular genotyping (MLST and MLVA), and genome sequencing, were employed to characterize the two B. abortus strains. The seroprevalence of brucellosis in marmots was 7.0% (80/1146) by serum tube agglutination test (SAT); one Brucella strain was recovered from these positive samples, and another Brucella strain from a human. Two strains were identified as B. abortus bv. 1 and were susceptible to all eight drugs examined. The distribution patterns of the accessory genes, virulence associated genes, and resistance genes of the two strains were consistent, and there was excellent collinearity between the two strains on chromosome I, but they had significant SVs in chromosome II, including inversions and translocations. MLST genotyping identified two B. abortus strains as ST2, and MLVA-16 analysis showed that the two strains clustered with strains from northern China. WGS-SNP phylogenetic analysis showed that the strains were genetically homogeneous with strains from the northern region, implying that strains from a common lineage were spread continuously in different regions and hosts. Seroprevalence and molecular clues demonstrated frequent direct or indirect contact between sheep/goats, cattle, and marmots, implying that wildlife plays a vital role in the maintenance and spread of B. abortus in the Qinghai-Tibet Plateau.

1378. Seroprevalence and risk factors for cysticercosis in Mexican-Americans in Starr County, Texas

Abstract Background Neurocysticercosis (NCC) is a parasitic infection caused by the tapeworm Taenia solium, and is a leading cause of epilepsy and chronic headaches in endemic areas including Latin America, Africa, and Asia. The epidemiology of NCC has not been well-studied in the United States to date, but small epidemiological studies suggest evidence of this disease in populations living in poverty and who have immigrated from an endemic region. There is a population living in Starr County, Texas along the Texas-Mexico border in whom the presence of other neglected tropical diseases has been demonstrated due to the intersection of poverty, climate, and high rate of immigration. Methods Our study was a serologic survey and risk factor analysis of cysticercosis in a pre-existing cohort of Mexican-Americans in Starr County, Texas. We used a triplex enzyme-linked immunoassay (ELISA) against cysticercosis-specific antigens and self-reported survey data and neighborhood-level variables to conduct a risk-factor analysis of seropositive participants. Results We identified an overall seropositivity to T. solium in 7.4% (45/605) of the cohort which likely represents a combination of parasite exposure, T. solium disease outside of the central nervous system, old calcified NCC, and viable or degenerating NCC. Female gender, specific occupation and indoor versus outdoor occupation were found to be significantly associated with cysticercosis seropositivity. Thirty-nine of the 45 seropositive participants were female (p 0.021), 26 were employed in healthcare, caregiving, or social service (p 0.009), and 42 were employed in an indoor occupation (p < 0.001). These occupations could pose a risk for T. solium transmission. A geospatial analysis of cases at the census tract level showed increased percentage of seropositivity centered around urban cities Rio Grande City and Roma, as well as smaller city La Grulla and census-designated place Alto Bonito. Conclusion There is a critical need to investigate these cysticercosis-seropositive cases with brain imaging to evaluate for neurocysticercosis, as well as conduct an epidemiological investigation to determine disease transmission in Starr County. Disclosures All Authors: No reported disclosures

A simulation-based method to inform serosurvey design for estimating the force of infection using existing blood samples.

The extent to which dengue virus has been circulating globally and especially in Africa is largely unknown. Testing available blood samples from previous cross-sectional serological surveys offers a convenient strategy to investigate past dengue infections, as such serosurveys provide the ideal data to reconstruct the age-dependent immunity profile of the population and to estimate the average per-capita annual risk of infection: the force of infection (FOI), which is a fundamental measure of transmission intensity. In this study, we present a novel methodological approach to inform the size and age distribution of blood samples to test when samples are acquired from previous surveys. The method was used to inform SERODEN, a dengue seroprevalence survey which is currently being conducted in Ghana among other countries utilizing samples previously collected for a SARS-CoV-2 serosurvey. The method described in this paper can be employed to determine sample sizes and testing strategies for different diseases and transmission settings.

Mapping the risk of exposure to Crimean-Congo haemorrhagic fever virus in the Iberian Peninsula using Eurasian wild boar (Sus scrofa) as a model

Crimean-Congo haemorrhagic fever (CCHF) virus (CCHFV) is a tick-borne zoonotic pathogen that can cause a lethal haemorrhagic disease in humans. Although the virus appears to be endemically established in the Iberian Peninsula, CCHF is an emerging disease in Spain. Clinical signs of CCHFV infection are mainly manifested in humans, but the virus replicates in several animal species. Understanding the determinants of CCHFV exposure risk from animal models is essential to predicting high-risk exposure hotspots for public health action. With this objective in mind, we designed a cross-sectional study of Eurasian wild boar (Sus scrofa) in Spain and Portugal. The study analysed 5,291 sera collected between 2006 and 2022 from 90 wild boar populations with a specific double-antigen ELISA to estimate CCHFV serum prevalence and identify the main determinants of exposure probability. To do so, we statistically modelled exposure risk with host- and environment-related predictors and spatially projected it at a 10 × 10 km square resolution at the scale of the Iberian Peninsula to map foci of infection risk. Fifty-seven (63.3 %) of the 90 populations had at least one seropositive animal, with seroprevalence ranging from 0.0 to 88.2 %. Anti-CCHFV antibodies were found in 1,026 of 5,291 wild boar (19.4 %; 95 % confidence interval: 18.3–20.5 %), with highest exposure rates in southwestern Iberia. The most relevant predictors of virus exposure risk were wild boar abundance, local rainfall regime, shrub cover, winter air temperature and soil temperature variation. The spatial projection of the best-fit model identified high-risk foci as occurring in most of western and southwestern Iberia and identified recently confirmed risk foci in eastern Spain. The results of the study demonstrate that serological surveys of CCHFV vector hosts are a powerful, robust and highly informative tool for public health authorities to take action to prevent human cases of CCHF in enzootic and emergency settings.

Molecular and serological detection of Anaplasma spp. in small ruminants in an area of Cerrado Biome in northeastern Brazil

Anaplasmosis, caused by bacteria of the genus Anaplasma, is an important tick-borne disease that causes economic losses to livestock farms in many countries. Even though Anaplasma spp. have been detected in goats and sheep worldwide, few studies investigate the occurrence and genetic identity of these agents in small ruminants from Brazil. Thus, this work aimed to detect and determine the genetic identity of Anaplasma spp. in small ruminants from the Baixo Parnaíba region, state of Maranhão, northeastern Brazil. For this purpose, blood samples were collected from 161 animals (91 goats; 70 sheep) from 4 municipalities in the Baixo Parnaíba region. Sheep and goat serum samples were subjected to recombinant membrane surface protein (MSP5)-based iELISA. Whole blood samples were subject to DNA extraction and molecular diagnosis using PCR assays for Anaplasma spp. targeting msp1β, msp1α, 16S rRNA and msp4 genes. Positive samples were sequenced and then subjected to Anaplasma marginale msp1α genetic diversity analysis and phylogenetic inferences based on the 16S rRNA and msp4 genes. The serological survey detected the presence of anti-A. marginale IgG antibodies in 18 animals (11.1%): 2.9% (2/70) sheep and 17.4% (16/91) goats. Anaplasma marginale DNA was detected in 2 goats (1.2%) using qPCR based on the msp1β gene. Two distinct A. marginale msp1α strains, namely α β and α β ΓγΓγΓγΓγ were found in the infected goats, each one found in a different animal, both belonging to the H genotype. Phylogenetic analysis based on the 16S rRNA gene showed the sequences positioned in three different clades and grouped with sequences from ‘Candidatus Anaplasma boleense’, A. platys and A. marginale. Phylogenetic inferences based on the msp4 gene positioned the sequence variants in the A. marginale clade. The present work represents the first molecular detection of sequence variants phylogenetic associated to ‘Candidatus Anaplasma boleense’ and A. platys and α β and α β ΓγΓγΓγΓγ in goats from Brazil.

Serological and molecular survey of brucellosis and chlamydiosis in dromedary camels from Tunisia

The present sero-epidemiological survey was designed and conducted to scrutinize the current status of camel-related brucellosis and chlamydiosis in Tunisia. Whole blood and serum samples were collected from 470 dromedaries (Camelus dromedarius) from eight different Tunisian governorates. Serum samples were subjected to indirect enzyme-linked immunosorbent assay (iELISA). The detection of Brucella and Chlamydia DNA was performed using conventional PCR targeting the bcsp-31 and 16S rRNA gene, respectively. Overall, 10/470(2.12%) and 27/470 (5.75%) camels were revealed seropositive to Brucella and Chlamydia, respectively. Multivariate logistic regression analysis showed different risk factors associated with these infections. Meaningful high rates of seropositivity of brucellosis (9.5%; p=0.000; OR=64.193) and chlamydiosis (22.6%; p=0.000; OR=42.860) were noted among camels showing previous abortions in particular for aged females. Besides, Chlamydia seropositivity is significantly important during winter (12.5%; p= 0.009; OR= 27.533), and in camels raised in small farms (11.4%, p= 0.000, OR=86.052). Molecular analysis revealed no positivity from all analyzed blood samples. These findings indicate the involvement of camels in the epidemiology of these abortive infectious diseases. This raises awareness and serious public health concern for infectious camel diseases in order to develop further diagnostic improvements and effective control strategies.

Seroprevalence of Crimean-Congo hemorrhagic fever virus among people living with HIV in Brazzaville, Congo and among blood donors in Bamako, Mali

Crimean-Congo hemorrhagic fever virus (CCHFV) is the causative agent of Crimean-Congo hemorrhagic fever (CCHF), a highly contagious and potentially fatal emerging disease. We assessed CCHFV seroprevalence by conducting a serological survey of two cohorts from Brazzaville, Congo and Bamako, Mali. We retrospectively screened 581 sera samples, including 352 from monitoring centers for people living with HIV (PLWH) in Brazzaville and 229 provided by the Blood Transfusion Center at Gabriel Touré Hospital in Bamako. An ELISA kit (ID Screen® CCHF Double Antigen Multi-species, Innovative Diagnostics) was used to detect total anti-CCHFV antibodies in serum. CCHFV seroprevalence was 0.6% in the PLWH cohort in Brazzaville, all in a peri‑urban area near livestock/agriculture, and 1.75% in a cohort of blood donors in Bamako, half living in a peri‑urban area near livestock/agriculture and the others performing risk-exposure activities, such as working as a butcher or with frequent rural travels. PLWH from Brazzaville were mostly female, older, and more highly educated, with a tertiary sector activity and living in an urban biotope without livestock/agricultural activities in the surroundings, in contrast to the blood donors of Bamako, who were younger and more likely to live in peri‑urban/rural areas with livestock/agricultural activities in the surroundings. Despite a low CCHFV seroprevalence, our study indicates human contact with CCHFV in sub-urban areas of the capital cities of Congo and Mali associated with previously described CCHFV risk factors.

Serological and molecular survey of canine distemper virus in red foxes (Vulpes vulpes): Exploring cut-off values and the use of protein A in ELISA tests

The wide distribution and ecological plasticity of the red fox (Vulpes vulpes) make it a potential reservoir for many infectious diseases shared with domestic and wild carnivores. One of such diseases is canine distemper, which is caused by an RNA virus and its main domestic reservoir is the dog. However, other carnivores can also participate in its maintenance, as shown by the recent upsurge of reported cases in wildlife in many parts of the world, and by the fact that red foxes may act as true reservoirs for canine distemper virus (CDV). The lack of validated serological tests for wildlife or other non-target species may be a handicap for monitoring this virus. In this study, serological assays were compared in 147 red fox sera using a commercial ELISA validated for its use in dogs and a non-specific modified ELISA with Protein A peroxidase conjugate to detect bound antibodies. In addition, the presence of CDV RNA in brain, spleen, lung, and liver samples from 144 foxes was investigated by a RT-qPCR. Through the comparison of the results of both ELISAs and the use of a finite mixture model of the optical density values obtained by both techniques, we adjusted the cut-off point of the commercial ELISA to obtain the seroprevalence in foxes. The overall seroprevalence detected was 53.7% (79/147) and 57.1% (84/147) by the commercial and modified ELISA, respectively, with a moderate agreement according to Cohen’s Kappa statistic (κ = 0.491, z = 5.97, p < 0.0001). CDV RNA was detected in 30 out of 144 foxes, which resulted in 20.8% of CDV-infected foxes. At individual level, the results obtained by relating the serological status and the presence/absence of RNA in different organs were explained in terms of the pathogenesis of the infection. Our results highlight the convenience of adjusting the cut-off point when using an ELISA assay developed in domestic dogs for its use in foxes. Moreover, Protein A is confirmed to be a good alternative to be used in red foxes, presenting a good reactivity towards its IgG.

Serological and Molecular Survey of Brucella Species in Owners and Their Dogs Living on Island and Mainland Seashore Areas of Brazil.

Background: Although Brucella abortus, Brucella suis, and Brucella canis may infect humans and dogs worldwide, no study to date has assessed and compared owners and their dogs between island and mainland seashore areas. Materials and Methods: Accordingly, the study herein has applied serological tests, including Microplate Agglutination Test with 2-Mercaptoethanol, immunochromatographic assay, and Rose Bengal Test, and a Brucella genus-specific PCR assay to 195 owners and their 148 dogs living on 1 mainland seashore area and three nearby oceanic islands of southern Brazil. Results: No seropositivity to B. abortus and B. suis was detected in owner or dog sera. Anti-B. canis seropositivity was observed in 3/148 (2.0%) dogs, but no owner sample was seropositive to B. canis. In addition, all blood samples from both owners and dogs were negative on Brucella genus-specific PCR assay. Conclusions: The seropositive dogs were not related and lived on the seashore mainland area of Guaraqueçaba city. The absence of seropositivity on the islands and the low seropositivity on the seashore mainland could be attributed to geographic isolation, and suggest the low impact of the disease in the region. Despite being a zoonotic disease, brucellosis by B. canis is not included in the National Program for Control and Eradication of Brucellosis, and its diagnosis and notification are not mandatory. The presence of seropositive dogs highlights the risk to human health and the importance of epidemiological surveillance actions in the region, as well as the need for the implantation of preventive measures to avoid the transmission of the pathogen.

Prevalence of Undiagnosed Monkeypox Virus Infections during Global Mpox Outbreak, United States, June-September 2022.

Since May 2022, mpox has been identified in 108 countries without endemic disease; most cases have been in gay, bisexual, or other men who have sex with men. To determine number of missed cases, we conducted 2 studies during June-September 2022: a prospective serologic survey detecting orthopoxvirus antibodies among men who have sex with men in San Francisco, California, and a retrospective monkeypox virus PCR testing of swab specimens submitted for other infectious disease testing among all patients across the United States. The serosurvey of 225 participants (median age 34 years) detected 18 (8.0%) who were orthopoxvirus IgG positive and 3 (1.3%) who were also orthopoxvirus IgM positive. The retrospective PCR study of 1,196 patients (median age 30 years; 54.8% male) detected 67 (5.6%) specimens positive for monkeypox virus. There are likely few undiagnosed cases of mpox in regions where sexual healthcare is accessible and patient and clinician awareness about mpox is increased.

The burden of the coronavirus disease 2019 virus infection in Burkina Faso: Results from a World Health Organization UNITY population-based, age-stratified sero-epidemiological investigation.

This study aimed to estimate the anti-SARS-CoV-2 antibody seroprevalence in the general population of Bobo-Dioulasso and Ouagadougou (Burkina Faso). We collected from March to April 2021 blood samples from randomly selected residents in both main cities based on the World Health Organization (WHO) sero-epidemiological investigations protocols and tested them with WANTAI SARS-CoV-2 total antibodies enzyme-linked immunosorbent assay (ELISA) kits intended for qualitative assessment. We also recorded participants' socio-demographic and clinical characteristics and information on exposure to SARS-CoV-2. Data were analysed with descriptive and comparative statistics. We tested 5240 blood samples collected between 03 March and 16 April 2021. The overall test-adjusted seroprevalence for SARS-CoV-2 antibodies was (67.8% [95% CI 65.9-70.2]) (N = 3553/3982). Seroprevalence was highest among participants aged 15-18 years old (74.2% [95% CI 70.5-77.5]) (N = 465/627), compared with those aged 10-14 years old (62.6% [95% CI 58.7-66.4]) (N = 395/631), or those over 18 (67.6% [95% CI 66.2-69.1]) (N = 2693/3982). Approximately 71.0% (601/860) of participants aged 10-18 years old who tested positive for SARS-CoV-2 antibodies experienced no clinical COVID-19 symptoms in the weeks before the survey, compared with 39.3% (1059/2693) among those aged over 18 years old. This study reports the results of the first known large serological survey in the general population of Burkina Faso. It shows high circulation of SARS-CoV-2 in the two cities and a high proportion of asymptomatic adolescents. Further studies are needed to identify the SARS-CoV-2 variants and to elucidate the factors protecting some infected individuals from developing clinical COVID-19.

SARS-CoV-2 seroprevalence in French 9-year-old children and their parents after the first lockdown in 2020

IntroductionChildren have been significantly less affected by COVID-19 than adults and presented with milder and less symptomatic forms of the disease. However, there has been suggestion that children older than 10 years and adolescents exhibits features closer to that of young adults. Most studies combine children in different age-groups and lack sufficient numbers to explore in detail age specificities. We report data on a population-based sample of 2,555 children at the pivotal age of 9 years.MethodsIn April 2020, the participants in two French nationwide cohorts of children, Elfe and Epipage2, were invited to take part into an online survey about Covid related symptoms and family life during the lockdown. A second questionnaire was sent on May 5. This questionnaire also proposed to the child included in the cohort and to one of his/her parents to take part into a capillary blood collection for Covid serology. Families who agreed to the serological survey were sent kits for dried blood spots self-sampling (DBS) with instructions. Samples were processed with a commercial Elisa test (Euroimmun®, Lübeck, Germany) to detect anti-SARS-CoV-2 antibodies (IgG) directed against the S1 domain of the spike protein of the virus.ResultsChildren's acceptance rate for the serological survey was around 60%. 2,555 serological results were analyzed. The weighted prevalence of a positive Elisa Spike serology was 2.8% in 9 yr-old children (95% CI: 1.7%–4.0%). Positive serology was found in 8.6% (7.4%–9.7%) of parents who provided blood. There was a significant association (p &amp;lt; 0.001) between serology of the child and parent from the same household with an odds ratio of 13.8 (7.9–24.2).DiscussionWe have shown that 9-yr old children had a lower susceptibility to SARS-Cov2 infection than adults with the initial Chinese strain, similar to younger children and estimated that around 3% of them have developed antibodies against SARS-Cov2 in France after the first wave of the Covid-19 epidemics.

Surveillance for Zoonotic Pathogens and Inuit Qaujimajatuqangit of Ringed Seals (nattiit) (Pusa hispida) in Frobisher Bay and Eclipse Sound, Nunavut, Canada

Ringed seals (Pusa hispida) (nattiq (s.), nattiit (pl.) [Inuktut]) provide an important food staple for Nunavummiut (Indigenous residents of Nunavut). We studied the health of nattiit harvested by hunters from Baffin Island, Nunavut, via Inuit Qaujimajatuqangit and veterinary science. We conducted serological surveys and polymerase chain reaction (PCR) for select zoonotic pathogens, including Brucella spp., Erysipelothrix rhusiopathiae, Leptospira interrogans, and Toxoplasma gondii, in 55 nattiit from Frobisher Bay (FB) and 58 nattiit from Eclipse Sound (ES). We used a digestion assay to determine the presence of Trichinella spp. larvae in muscle samples from these seals. We conducted interviews with nine Local Knowledge Holders (LKHs) from Iqaluit (FB) and nine from Pond Inlet (ES) to gather their observations about nattiq health. The hunters evaluated nattiq health through a combination of behavior, nutritional condition, and appearance of skin and organs. They rarely observed severely ill nattiit. Hunters from ES but not from FB observed declining nattiit population numbers. In both regions, they observed increased numbers of harp seals (Phoca groenlandica). Frequencies of natural exposure among nattiit from FB and ES, based on seroprevalence, were 20.5% and 37% for Brucella spp., 25% and 11% for E. rhusiopathiae, 93% and 100% for L. interrogans, and 10% and 27% for T. gondii, respectively; PCR was negative for these pathogens in organs and tissues of seropositive animals. We did not detect larvae of Trichinella spp. Knowledge and experience from the LKHs in assessing nattiq health, complemented by negative findings from direct detection methods, provide reassurance about the safety of nattiit as country food, despite their exposure to some zoonotic pathogens in their natural environment.

Step-by-step towards regular health examination surveys in Portugal

Abstract The 1st National Health Examination Survey was performed in Portugal in 2015 following the EHES procedures. It consisted of a cross-sectional population-based study representative at regional and national level. Individuals aged 25-74 years, residing in Portugal were selected from the national health users’ registry through multi-stage stratified probabilistic sampling. Data was collected in primary care units and included blood pressure, height, weight, hip and waist measurements, blood collection for lipid profile, HbA1c and blood count and a general health questionnaire. A biobank was created which includes serum, plasma, DNA and whole blood of consenting INSEF participants. Nationally representative quality epidemiological data is now available for public health monitoring, planning and research. The data has provided several indicators for the National Health Programs such as tobacco consumption, prevalence of diabetes, obesity, hypertension and dyslipidaemia for the National Program for Tobacco Prevention and control, National Program of Diabetes and National Program for the Promotion of Healthy Eating. In addition, indicators such as excessive salt consumption were used as a starting point for healthy eating campaigns towards reducing its use. The second National Examination Survey is currently being planned and is expected to be held in 2025 in a consortium with the National Food and Nutrition Survey and with the National Serological Survey. The planning and implementation of a single health survey that associates self-reported information on health status and disease, behavioural health determinants, including a detailed dietary and physical activity component, physical examination, and collection of biological products (blood and urine) would constitute an essential source of knowledge for the monitoring, evaluation of public health interventions, and for population-based epidemiological research.

Unraveling swine hepatitis E in the central region of Argentina through ELISA development and epidemiological insights

Hepatitis E virus (HEV) is a public health concern globally, causing acute viral hepatitis in humans. Genotype-3 HEV (HEV-3), the most frequently genotype detected in South America, is zoonotic and the main reservoirs are the domestic pig and wild boar. Circulation of HEV-3 in Argentina has been confirmed in humans as well as in pig herds, wild boar and environmental waters. However, data are scarce mainly due to the inaccessibility of serological assays in this country. In order to provide insights in the epidemiology of HEV in swine in Argentina, we developed an indirect ELISA based on the native recombinant protein ORF2 and conducted a serological survey to determine the prevalence of seropositive swine in small-scale pig farms in the central region of Argentina. The method was evaluated in a panel of 157 serum samples, resulting in relative sensitivity of 98.6 % (95 % CI 95 %−100 %) and relative specificity of 97.7 % (95 % CI 94 %−100 %) compared to a commercial test. An almost perfect agreement was obtained between the two tests (Kappa index of 0.961). A survey on 294 samples from 49 small-scale farms resulted in a seropositivity rate of 54 %. Seropositive animals were found in 34 out of 49 (69.4 %) farms. Most of the farms (70.6 %) had over 50 % of seropositive animals. The wide spreading of HEV in the swine population of Tandil, Argentina, underscore the need to better understand the epidemiology of HEV in the region, enabling the implementation of targeted interventions to mitigate the impact of this virus on public health.

IMPACT OF COVID-19 ON PEOPLE LIVING WITH HIV IN MADAGASCAR: A SARS-COV2 SERO-PREVALENCE SURVEY.

In Madagascar, no study has reported the impact of COVID-19 on people living with HIV (PLHIV). The present work aimed to analyze the seroprevalence of SARS-CoV-2 in Malagasy PLHIV before and during the three waves of COVID-19 pandemic.This is a retrospective study. We conducted a retrospective serological survey in PLHIV followed up for HIV viral load (VL) monitoring at the Centre d'Infectiologie Charles Mérieux Madagascar (CICM) between June 2019 and April 2022. The presence of IgM and/or IgG antibodies against SARS-CoV-2 nucleoprotein was detected using a rapid diagnostic test (COVID-PRESTO®). A seroprevalence of 2.5% was found in the 877 patients tested before March 2020, compared to 25.4% (512/2,011) between March 2020 and April 2022. This seroprevalence was 21.7%, 22.3% and 60.1% after the first, second and third waves of COVID-19, respectively. We observed a marginally significant difference (p = 0.043) in SARS-CoV-2 seroprevalence between patients on highly active antiretroviral therapy (HAART) (27.5%) and those who were not (23.7%). No statistically significant difference was observed between PLHIV with undetectable HIV VL (27.4%) and the different detectable VL categories (p>0.05). Our data show the presence of antibodies to SARS-CoV-2 among PLHIV as early as December 2019 in Madagascar. At least 25.4% (512/2,011) of Malagasy PLHIV have been in contact with SARS-CoV-2 since March 2020. There is no significant relation between HIV-1 VL and SARS-CoV-2 seroprevalence. Additional studies with more robust assays in the general population are needed for a detailed knowledge of SARS-CoV-2 impact in Madagascar.

Unmet need for modern contraception by HIV status: findings from community—based studies implemented before and after earlier ART initiation program in rural Tanzania

BackgroundTanzania Health policy insists on the need to provide all women access to contraception despite HIV status. We used data from two HIV epidemiologic serological surveys carried out at different periods of ART provision in rural Tanzania to assess the level of unmet need for modern contraception by HIV status and associated factors.MethodsWe performed secondary data analysis of two surveys conducted at the Magu Health and Demographic Surveillance System site, in Mwanza, Tanzania. Information on unmet need for modern contraception was derived from fertility desire and contraception use. Unmet need, HIV status, and socioeconomic and demographic variables were analysed. The percentage of women with unmet needs for modern contraception by HIV status is presented for the 2012 and 2017 surveys. Bivariate and multivariate analyses using logistic regression were used to investigate associated factors showing adjusted odds ratios (aORs) and 95% confidence intervals (95% CIs).ResultsData from 3352 and 3196 women aged 15–49 years collected in the 2012 and 2017 surveys, respectively, were analysed. The percentages of women with unmet needs for modern contraception in the 2012 and 2017 surveys were 30.9% (95% CI 29.4–32.6) and 31.6% (95% CI 30.0–33.3), respectively. The unmet need for modern contraception was 26% lower in HIV-uninfected women in 2012 (aOR = 0.74; 95% CI 0.569–0.973); p = 0.031). Risk factors for unmet need for modern contraception in 2012 were HIV uninfected (adjusted OR = 0.74; 95% CI 0.569–0.973); p = 0.031), married marital status (adjusted OR = 0.768; 95% CI 0.743–0.794); p < 0.0001), higher education (adjusted OR = 0.768; 95% CI 0.743–0.794); p < 0.0001), and taking alcohol (adjusted OR = 0.768; 95% CI 0.743–0.794); p < 0.0001). Only two factors were associated with unmet need for modern contraception in 2017: married marital status (adjusted OR = 0.46; 95% CI 0.305–0.722); p = 0.001) and women who earned for their families (aOR = 0.66; 95% CI 0.494–0.887); p = 0.006).DiscussionNearly one-third of women had an unmet need for modern contraception, which was lower in HIV-uninfected women than in WLHIV-infected women. The study has identified women whose demand for contraception has not been met: WLHIV, post marital women, women with low education and women who were reported to earn money for their families. Family planning interventions should be tailored to these groups of women.

Distribution of Aedes mosquito species along the rural–urban gradient in Lambaréné and its surroundings

BackgroundAedes albopictus and Aedes aegypti are known for their potential as vectors of dengue (DENV) and chikungunya (CHIKV) viruses. However, entomological surveys are mostly carried out during epidemics. In Gabon where outbreaks of both viruses have occurred, there is no vector control program targeting these arboviruses. Therefore, we assessed the presence of Aedes species along a rural–urban gradient in Lambaréné (Gabon) and its surroundings and determined ecological factors associated to their presence.MethodsAn entomological survey was conducted in Lambaréné and its surrounding rural areas. Mosquitoes were collected with aspirators around human dwellings, and ecological and environmental data were collected from each study area. Morphological identification keys were used to identify Aedes species. RNA was extracted from pools of female mosquitoes and amplified by RT-qPCR to detect the presence of DENV and CHIKV.ResultsOverall, the most common vector collected was Aedes albopictus (97%, 4236/4367 specimens), followed by Aedes aegypti (3%, 131/4367). Albopictus vectors was more abundant in the rural area (Wilcoxon signed-rank test, Z = 627, P = 0.043) than in the urban area. In the urban area, a higher number of mosquitoes (45%) were recorded in the economic zone (zone 3) than in the historical and administrative zones (zone 1 and 2). In the rural area, the proportions of species numbers were significantly higher along the south rural transect (92%) compared to the north rural transect (Wilcoxon signed-rank test, Z = 43, P ˂ 0.016). We also noted a high abundance of vectors in environments characterized by monocultures of Hevea brasiliensis (Hevea) and Manihot esculenta (cassava) (Kruskal–Wallis H-test, H = 25.7, df = 2, P < 0.001). Finally, no mosquito pools were positive for either DENV or CHIKV.ConclusionAedes albopictus was the dominant vector across the study sites due to its high invasiveness capacity. This presence re-affirms the potential for local transmission of both DENV and CHIKV, as indicated previously by serological surveys conducted in our study area, even though no transmission was detected during the current study. These findings underscore the need for regular arbovirus surveillance in the study region, with the aim of supporting vector control efforts in the event of outbreaks.Graphical