7 research outputs found

    Longitudinal profile of antibody response to SARS-CoV-2 in patients with COVID-19 in a setting from Sub-Saharan Africa: A prospective longitudinal study.

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    BACKGROUND Serological testing for SARS-CoV-2 plays an important role for epidemiological studies, in aiding the diagnosis of COVID-19, and assess vaccine responses. Little is known on dynamics of SARS-CoV-2 serology in African settings. Here, we aimed to characterize the longitudinal antibody response profile to SARS-CoV-2 in Ethiopia. METHODS In this prospective study, a total of 102 PCR-confirmed COVID-19 patients were enrolled. We obtained 802 plasma samples collected serially. SARS-CoV-2 antibodies were determined using four lateral flow immune-assays (LFIAs), and an electrochemiluminescent immunoassay. We determined longitudinal antibody response to SARS-CoV-2 as well as seroconversion dynamics. RESULTS Serological positivity rate ranged between 12%-91%, depending on timing after symptom onset. There was no difference in positivity rate between severe and non-severe COVID-19 cases. The specificity ranged between 90%-97%. Agreement between different assays ranged between 84%-92%. The estimated positive predictive value (PPV) for IgM or IgG in a scenario with seroprevalence at 5% varies from 33% to 58%. Nonetheless, when the population seroprevalence increases to 25% and 50%, there is a corresponding increases in the estimated PPVs. The estimated negative-predictive value (NPV) in a low seroprevalence scenario (5%) is high (>99%). However, the estimated NPV in a high seroprevalence scenario (50%) for IgM or IgG is reduced significantly to 80% to 85%. Overall, 28/102 (27.5%) seroconverted by one or more assays tested, within a median time of 11 (IQR: 9-15) days post symptom onset. The median seroconversion time among symptomatic cases tended to be shorter when compared to asymptomatic patients [9 (IQR: 6-11) vs. 15 (IQR: 13-21) days; p = 0.002]. Overall, seroconversion reached 100% 5.5 weeks after the onset of symptoms. Notably, of the remaining 74 COVID-19 patients included in the cohort, 64 (62.8%) were positive for antibody at the time of enrollment, and 10 (9.8%) patients failed to mount a detectable antibody response by any of the assays tested during follow-up. CONCLUSIONS Longitudinal assessment of antibody response in African COVID-19 patients revealed heterogeneous responses. This underscores the need for a comprehensive evaluation of seroassays before implementation. Factors associated with failure to seroconvert needs further research

    Assessment of Human-Wildlife Conflict and the Attitude of Local Communities to Wild Animal Conservation around Borena Sayint National Park, Ethiopia

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    Human-wildlife conflict (HWC) has increased globally because of an increase in the human population, particularly in developing countries. This study was conducted to investigate the status of HWC and the attitude of local communities to wildlife conservation around Borena Sayint National Park, Northeastern Ethiopia. Data were collected between September 2017 and May 2018 using a face-to-face questionnaire survey (230), focus group discussions (7), and direct observation on the crop foraging. The data were analyzed using descriptive statistics, and the responses were compared using a nonparametric Pearson chi-square test. The majority of respondents (70%) reported the existence of HWC manifested because of the damage received to their assets (both crop and livestock). Canis aureus, Panthera pardus, Crocuta crocuta, and Papio hamadryas were stated as livestock depredators. Gelada, rabbit, porcupine, klipspringer, bushbuck, and duiker were considered as the major crop raiders. Over half (57.83%) of the respondents had a positive attitude, while others (36.09%) had a negative attitude towards the conservation of wildlife due to frequently faced problems. Respondents in different villages differed significantly (χ2 = 27.385, DF = 12, P<0.05) in their attitude towards wildlife. Possible mitigation actions need to be undertaken to reduce the wildlife damage such that wildlife can sustainably be managed in the park

    Activity Budget and Feeding Ecology of Geladas (Theropithecus gelada obscurus) around Abogedam Church West of Debre Berhan Town, Ethiopia

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    Geladas are the most distinctive of Ethiopian endemic mammals, representing the last extant species of primate genus that have a very restricted distribution in the northern Ethiopian plateau. The activity budget and feeding ecology of geladas (Theropithecus gelada obscurus) were studied around Abogedam Church, Ethiopia, from May to October 2014, encompassing dry and wet seasons. The scan sampling method was applied to collect behavioural data on the identified band. Activity scans were collected at 15-minute intervals for up to five minutes duration from 0700 to 1730 h. The activity recorded for each individual was the first activity that lasts for five seconds. During each scan, individuals were recorded as performing activities: feeding, moving, resting, playing, aggression, grooming, sexual activity, and others. On average, geladas devoted 57.19% feeding, 14.82% resting, 14.92% moving, 4.83% playing, 2.53% aggression, 4.14% grooming, 1.23% sexual activity, and 0.34% other activities such as vocalization, defecation, and urination. Forty-one plant species were consumed by geladas that belonged to 18 families of which 53.66% were grasses. This study provides basic information on further studies and motivates conservationists to plan the management of unprotected areas at the vicinity of agricultural lands where such endemic animals dwell

    Assessment of crop foraging by hamadryas baboons (Papio hamadryas) in and around Borena-Sayint National Park, northern Ethiopia

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    Crop foraging is a widespread form of human-wildlife conflict adjacent to protected areas. It causes a great economic loss for subsistence communities hindering efforts in conservation endeavors. Hamadryas baboons (Papio hamadryas) occur both in the lowland and highland ecosystems of Ethiopia. The species is known for its crop foraging behavior across its ranges. However, little is known about human-hamadryas baboon interactions manifested in crop foraging in the Ethiopian highlands. Thus, this study aimed to provide data on the magnitude of hamadryas baboon conflict with the local community in and around Borena-Sayint National Park (BSNP), northern Ethiopia. We collected data from January to July 2018 using a questionnaire survey of sample households in the surrounding local communities. We analyzed the attitude and perception of the local people towards hamadryas baboons using descriptive statistics. Local people estimated that hamadryas baboons damaged 120.2 kg of crops/household/year in and around BSNP. The species caused the highest damage to wheat (45.1 kg), barley (25.5 kg), potato (24.7 kg) and maize (20.1 kg) per household per year. The respondents reported that hamadryas baboons, from all incidents of crop foraging, caused the highest proportion of damage during the vegetative (48.2%) and harvesting (33.9%) stages of the cultivated foods. Local people reported that crop foraging was significantly greater during the dry season than in the wet season. Respondents mainly depend on guarding (43.6%) and shouting (32.8%) to prevent their cultivated crops from the visit of hamadryas baboons. About 12% of the respondents who experienced crop damage killed hamadryas baboons in retaliation. The intense interaction between hamadryas baboons and humans may pose a serious threat to the survival of the species unless appropriate management actions are taken. The findings of this study are crucial for developing management plans and implementing successful conservation strategies

    Abundance, Diversity, and Distribution of Primates at Welel Mountain, Kellem Wollega Zone, Oromia Region, Ethiopia

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    Primates are the mammals of the order Primate that is characterized by advanced development of binocular vision and enlargement of the cerebral hemispheres. The aim of this study was to investigate the abundance, diversity, and distribution of primates on Welel Mountain. From August 2017 to February 2018, we collected data from different parts of Welel Mountain during wet and dry seasons of the year and analyzed them using SPSS version 20. We identified four primate species: Chlorocebus aethiops, Cercopithecus mitis, Papio anubis, and Colobus guereza. We conducted t-test analysis for abundance and distribution of primates in wet and dry season of the year, and the P value obtained was 0.20. The mean percentages of primates in forest, woodland, and shrubs were 43.16%, 32.26%, and 24.58%, respectively. Shannon-Wiener diversity index (H′) value was higher in wet season than in dry season. The current study showed that the species are distributed more evenly in wet season than in dry season, and the number of young individuals is more than that of adults. This indicates that currently the status of primates population on Welel Mountain is good. Therefore, to keep the status of primates in the study area effective, wildlife management and conservation policy should be formulated

    Wild geladas (Theropithecus gelada) in crops – more than in pasture areas - reduce aggression and affiliation

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    Human–primate interfaces are expanding and, despite recent studies on primates from peri-urban environments, little research exists on the impact of agriculture and/or pasture areas on primate social behavior and health. We assessed how crop/pasture areas potentially alter social behavior and health of wild geladas (Theropithecus gelada) frequenting the unprotected area of Kundi (Ethiopia). We predicted that compared to pasture areas, crop areas (i) would be more challenging for geladas (prediction 1) and (ii) would have a greater impact on both aggressive and affiliative behavior, by reducing grooming time and enhancing competition (prediction 2). During January–May 2019 and December 2019–February 2020, we collected data (via scan, focal animal sampling, and video analyses) on direct human disturbance, external signs of pathologies and social behavior of 140 individuals from 14 one-male units and two all-male units. Animals experienced the highest level of human disturbance in crop areas (in line with prediction 1). Individuals from the groups preferentially frequenting crop areas showed the highest prevalence of external signs of pathologies consistent with chemical and biological contamination (alopecia/abnormally swollen parts). We collected 48 fecal samples. Samples from frequent crop users contained the highest rates of parasitic elements/gram (egg/larva/oocyst/cyst) from Entamoeba histolytica/dispar, a parasite common in human settlements of the Amhara region. In crop areas, subjects spent less time grooming but engaged in lower rates of intense aggression (in partial agreement with prediction 2). We speculate that the reduction in social behavior may be a tactic adopted by geladas to minimize the likelihood of detection and maximize food intake while foraging in crops

    Longitudinal profile of antibody response to SARS-CoV-2 in patients with COVID-19 in a setting from Sub-Saharan Africa: A prospective longitudinal study

    No full text
    BACKGROUND: Serological testing for SARS-CoV-2 plays an important role for epidemiological studies, in aiding the diagnosis of COVID-19, and assess vaccine responses. Little is known on dynamics of SARS-CoV-2 serology in African settings. Here, we aimed to characterize the longitudinal antibody response profile to SARS-CoV-2 in Ethiopia. METHODS: In this prospective study, a total of 102 PCR-confirmed COVID-19 patients were enrolled. We obtained 802 plasma samples collected serially. SARS-CoV-2 antibodies were determined using four lateral flow immune-assays (LFIAs), and an electrochemiluminescent immunoassay. We determined longitudinal antibody response to SARS-CoV-2 as well as seroconversion dynamics. RESULTS: Serological positivity rate ranged between 12%-91%, depending on timing after symptom onset. There was no difference in positivity rate between severe and non-severe COVID-19 cases. The specificity ranged between 90%-97%. Agreement between different assays ranged between 84%-92%. The estimated positive predictive value (PPV) for IgM or IgG in a scenario with seroprevalence at 5% varies from 33% to 58%. Nonetheless, when the population seroprevalence increases to 25% and 50%, there is a corresponding increases in the estimated PPVs. The estimated negative-predictive value (NPV) in a low seroprevalence scenario (5%) is high (>99%). However, the estimated NPV in a high seroprevalence scenario (50%) for IgM or IgG is reduced significantly to 80% to 85%. Overall, 28/102 (27.5%) seroconverted by one or more assays tested, within a median time of 11 (IQR: 9-15) days post symptom onset. The median seroconversion time among symptomatic cases tended to be shorter when compared to asymptomatic patients [9 (IQR: 6-11) vs. 15 (IQR: 13-21) days; p = 0.002]. Overall, seroconversion reached 100% 5.5 weeks after the onset of symptoms. Notably, of the remaining 74 COVID-19 patients included in the cohort, 64 (62.8%) were positive for antibody at the time of enrollment, and 10 (9.8%) patients failed to mount a detectable antibody response by any of the assays tested during follow-up. CONCLUSIONS: Longitudinal assessment of antibody response in African COVID-19 patients revealed heterogeneous responses. This underscores the need for a comprehensive evaluation of seroassays before implementation. Factors associated with failure to seroconvert needs further research
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