Abstract
The human disease lymphatic filariasis causes the debilitating effects of elephantiasis and hydrocele. Lymphatic filariasis currently affects the lives of 90 million people in 52 countries. ...There are three nematodes that cause lymphatic filariasis, Brugia malayi, Brugia timori, and Wuchereria bancrofti, but 90% of all cases of lymphatic filariasis are caused solely by W. bancrofti (Wb). Here we use population genomics to reconstruct the probable route and timing of migration of Wb strains that currently infect Africa, Haiti, and Papua New Guinea (PNG). We used selective whole genome amplification to sequence 42 whole genomes of single Wb worms from populations in Haiti, Mali, Kenya, and PNG. Our results are consistent with a hypothesis of an Island Southeast Asia or East Asian origin of Wb. Our demographic models support divergence times that correlate with the migration of human populations. We hypothesize that PNG was infected at two separate times, first by the Melanesians and later by the migrating Austronesians. The migrating Austronesians also likely introduced Wb to Madagascar where later migrations spread it to continental Africa. From Africa, Wb spread to the New World during the transatlantic slave trade. Genome scans identified 17 genes that were highly differentiated among Wb populations. Among these are genes associated with human immune suppression, insecticide sensitivity, and proposed drug targets. Identifying the distribution of genetic diversity in Wb populations and selection forces acting on the genome will build a foundation to test future hypotheses and help predict response to current eradication efforts.
In June 2021, the World Health Organization (WHO), recognizing the need for new diagnostics to support the control and elimination of onchocerciasis, published the target product profiles (TPPs) of ...new tests that would support the two most immediate needs: (a) mapping onchocerciasis in areas of low prevalence and (b) deciding when to stop mass drug administration programs. In both instances, the test should ideally detect an antigen specific for live, adult O. volvulus female worms. The preferred format is a field-deployable rapid test. For mapping, the test needs to be ≥ 60% sensitive and ≥ 99.8% specific, while to support stopping decisions, the test must be ≥ 89% sensitive and ≥ 99.8% specific. The requirement for extremely high specificity is dictated by the need to detect with sufficient statistical confidence the low seroprevalence threshold set by WHO. Surveys designed to detect a 1-2% prevalence of a given biomarker, as is the case here, cannot tolerate more than 0.2% of false-positives. Otherwise, the background noise would drown out the signal. It is recognized that reaching and demonstrating such a stringent specificity criterion will be challenging, but test developers can expect to be assisted by national governments and implementing partners for adequately powered field validation.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The soil to atmosphere fluxes of greenhouse gases N2O, CH4 and CO2 and their relationships with soil characteristics were investigated in three tropical oceanic mangrove swamps (Teremaal, Likupang ...and Kema) in North Sulawesi, Indonesia. Mangrove soils in North Sulawesi were rich in organic carbon and nitrogen, but the greenhouse gas fluxes were low in these mangroves. The fluxes ranged −6.05–13.14μmolm−2h−1, −0.35–0.61μmolm−2h−1 and −1.34–3.88mmolm−2h−1 for N2O, CH4 and CO2, respectively. The differences in both N2O and CH4 fluxes among different mangrove swamps and among tidal positions in each mangrove swamp were insignificant. CO2 flux was influenced only by mangrove swamps and the value was higher in Kema mangrove. None of the measured soil parameters could explain the variation of CH4 fluxes among the sampling plots. N2O flux was negatively related to porewater salinity, while CO2 flux was negatively correlated with water content and organic carbon. This study suggested that the low gas emissions due to slow metabolisms would lead to the accumulations of organic matters in North Sulawesi mangrove swamps.
•North Sulawesi mangrove swamps are rich in soil organic carbon and nitrogen.•N2O, CH4 and CO2 fluxes from North Sulawesi mangrove soils are low.•CO2 flux is negatively correlated with soil water content and organic carbon.•High porewater salinity decreases N2O flux.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Despite the global interest and the unprecedented number of scientific studies triggered by the COVID-19 pandemic, few data are available from developing and low-income countries. In these regions, ...communities live under the threat of various transmissible diseases aside from COVID-19, including malaria. This study aims to determine the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) seroreactivity of antibodies from COVID-19 and pre-COVID-19 samples of individuals in Mali (West Africa). Blood samples from COVID-19 patients (n = 266) at Bamako Dermatology Hospital (HDB) and pre-COVID-19 donors (n = 283) from a previous malaria survey conducted in Dangassa village were tested by ELISA to assess IgG antibodies specific to the full-length spike (S) protein, the receptor-binding domain (RBD), and the receptor-binding motif (RBM
). Study participants were categorized by age, gender, treatment duration for COVID-19, and comorbidities. In addition, the cross-seroreactivity of samples from pre-COVID-19, malaria-positive patients against the three antigens was assessed. Recognition of the SARS-CoV-2 proteins by sera from COVID-19 patients was 80.5% for S, 71.1% for RBD, and 31.9% for RBM (
< 0.001). While antibody responses to S and RBD tended to be age-dependent, responses to RBM were not. Responses were not gender-dependent for any of the antigens. Higher antibody levels to S, RBD, and RBM at hospital entry were associated with shorter treatment durations, particularly for RBD (
< 0.01). In contrast, higher body weights negatively influenced the anti-S antibody response, and asthma and diabetes weakened the anti-RBM antibody responses. Although lower, a significant cross-reactive antibody response to S (21.9%), RBD (6.7%), and RBM (8.8%) was detected in the pre-COVID-19 and malaria samples. Cross-reactive antibody responses to RBM were mostly associated (
< 0.01) with the absence of current
infection, warranting further study.
ABSTRACT
Background
The sero‐epidemiological characteristics of SARS‐CoV‐2 infections in Mali are not yet well understood. This study assessed SARS‐CoV‐2 antibody seroprevalence and factors ...associated with antibody responses in the general population of Bamako, the capital city and epicenter of COVID‐19, to assess the magnitude of the pandemic and contribute to control strategy improvements in Mali.
Methods
A cross‐sectional survey was conducted in September 2022 to collect sociodemographic information, clinical characteristics, comorbid factors, and blood samples. ELISA was performed to determine anti‐Spike (anti‐S) and anti‐RBD antibody levels. A total of 3601 participants were enrolled in REDCap. R‐Studio was used for the statistical analysis. The chi‐squared (χ2) test was used to compare the proportions across different groups. Logistic regression models were used to elucidate factors associated with antibody responses.
Result
The sex ratio for female‐to‐male was 3.6:1. The most representative groups were the 20–29‐year‐olds (28.9%, n = 1043) and the 30–39‐year‐olds (26.9%, n = 967). The COVID‐19 vaccine coverage among the participants was 35.8%, with vaccines from Covishield AstraZeneca (13.4%), Johnson & Johnson (16.7%), Sinovac (3.9%), and BioNTech Pfizer (1.8%). Overall, S protein and RBD antibody seroprevalences were remarkably high in the study population (98% and 97%, respectively). Factors such as youth (1–9 years old) and male sex were associated with lower SARS‐CoV‐2 antibody responses, whereas COVID‐19 vaccinations were associated with increased antibody responses.
Conclusion
This serosurvey demonstrated the high seroprevalence of SARS‐CoV‐2 antibodies and highlighted the factors influencing antibody responses, while clearly underlining an underestimation of the pandemic in Mali.
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FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, UL, UM, UPUK
Ivermectin-based onchocerciasis elimination, reported in 2009-2012, for Bakoye and Falémé, Mali, supported policy-shifting from morbidity control to elimination of transmission (EOT). These foci are ...coendemic with lymphatic filariasis (LF). In 2007-2016 mass ivermectin plus albendazole administration was implemented. We report Ov16 (onchocerciasis) and Wb123 (LF) seroprevalence after 24-25 years of treatment to determine if onchocerciasis EOT and LF elimination as a public health problem (EPHP) have been achieved.
The SD Bioline Onchocerciasis/LF IgimmunoglobulinG4 biplex rapid diagnostic test (RDT) was used in 2186 children aged 3-10 years in 13 villages (plus 2 hamlets) in Bakoye and in 2270 children in 15 villages (plus 1 hamlet) in Falémé. In Bakoye, all-age serosurveys were conducted in 3 historically hyperendemic villages (1867 individuals aged 3 -78 years).
In Bakoye, IgG4 seropositivity was 0.27% (95% confidence interval CI = .13%-.60%) for both Ov16 and Wb123 antigens. In Falémé, Ov16 and Wb123 seroprevalence was 0.04% (95% CI = .01%-.25%) and 0.09% (95% CI = .02%-.32%), respectively. Ov16-seropositive children were from historically meso/hyperendemic villages. Ov16 positivity was <2% in ≤14 year-olds, and 16% in ≥40 year-olds. Wb123 seropositivity was <2% in ≤39 year-olds, reaching 3% in ≥40 year-olds.
Notwithstanding uncertainty in the biplex RDT sensitivity, Ov16 and Wb123 seroprevalence among children in Bakoye and Falémé is consistent with EOT (onchocerciasis) and EPHP (LF) since stopping treatment in 2016. The few Ov16-seropositive children should be skin-snip polymerase chain reaction tested and followed up.
Lymphedema (LE) is one the most disfiguring chronic manifestations of lymphatic filariasis. Its management relies primarily on limb hygiene and local care. A previous study in Ghana demonstrating a ...beneficial effect of doxycycline on LE led to the current multicenter trial on the efficacy of doxycycline in filarial LE. A randomized placebo-controlled trial was initiated in two rural health districts in Mali. Patients with LE stages 1–3 were randomized to receive either doxycycline (200 mg/day) or placebo over a 6-week monitored treatment period and were then followed every 6 months for 2 years. Both groups received materials for limb hygiene that was carried out daily for the entire 2-year study. The primary endpoint was lack of progression in LE stage at 24 months. One hundred patients were enrolled in each study arm. The baseline sociodemographic characteristics of each group were largely similar. There was no significant difference at month 24 after treatment initiation in the number of subjects showing progression in LE stage between the two treatment arms ( P = 0.5921). Importantly, however, the number of attacks of acute adenolymphangitis (ADLA) was reduced in both arms, but there was no significant difference between the two groups at any follow-up time point (all P >0.23). Doxycycline was well tolerated in those receiving the drug. When added to daily self-administered limb hygiene, a 6-week course of doxycycline (200 mg) was not superior to placebo in increasing the improvement associated with hygiene alone in LE volume, stage, or frequency of ADLA attacks over a 24-month period.
Historically the western sahelian dry regions of Mali are known to be highly endemic for cutaneous leishmaniasis (CL) caused by Leishmania major, while cases are rarely reported from the Southern ...savanna forest of the country. Here, we report baseline prevalence of CL infection in 3 ecologically distinct districts of Mali (dry sahelian, north savanna and southern savanna forest areas). We screened 195 to 250 subjects from 50 to 60 randomly selected households in each of the 6 villages (four from the western sahelian district of Diema in Kayes region, one from the central district of Kolokani and one from the southern savanna district of Kolodieba, region of Sikasso). The screening consisted of: 1 A Leishmanin Skin Test (LST) for detection of exposure to Leishmania parasites; 2 clinical examination of suspected lesions, followed by validation with PCR and 3 finger prick blood sample to determine antibody levels to sand fly saliva. LST positivity was higher in the western district of Diema (49.9%) than in Kolokani (24.9%) and was much lower in Kolondieba (2.6%). LST positivity increased with age rising from 13.8% to 88% in Diema for age groups 2-5 years and 41-65 years, respectively. All eight PCR-confirmed L. major CL cases were diagnosed in subjects below 18 years of age and all were residents of the district of Diema. Exposure to sand fly bites, measured by anti-saliva antibody titers, was comparable in individuals living in all three districts. However, antibody titers were significantly higher in LST positive individuals (P<0.0001). In conclusion, CL transmission remains active in the western region of Mali where lesions were mainly prevalent among children under 18 years old. LST positivity correlated to higher levels of antibodies to sand fly salivary proteins, suggesting their potential as a risk marker for CL acquisition in Mali.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Coastal lagoons are important geographic features because they provide various natural resources. Exploitative resource use and mismanagement may cause irreversible damage to the environment. This ...paper aims to review research and management based on the available spatial dataset in Segara Anakan, a rapidly shrinking lagoon in Indonesia, which is expected to disappear completely soon. We summarize knowledge from the earliest available publication in the 19th century (Dutch colonial time) to current times. There are three extreme patterns of changes: geomorphological, vegetation cover, and hydrological changes. These changes are basically interconnected. For example, the lagoon is continuing to shrink, while freshwater supply is higher than seawater supply, decreasing soil salinity. With this lesser saline environment, the understory mangrove species occupy and grow quick in the degraded mangrove area. Thus, mangrove seedlings have difficulty in surviving in competition with the understory plants. From this insight, a conceptual model was developed, and could be used in the management of the area. The available (spatial) data can be used to obtain more knowledge about the mangrove forest in the area.
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