An update on the mosquito species composition and diversity in western and North Western Uganda

Although the west and north western parts of Uganda are historically known homes to a number of mosquito species and arboviruses associated with morbidity and mortality, early studies were highly focal and limited to specific collection methods. We aimed to update mosquito species composition in areas where a febrile illness study had shown evidence of arboviruses circulating. Adult mosquito sampling was done outside and inside houses using light traps baited with solid carbon dioxide and pyrethrum spray respectively. All collected mosquitoes were identified using appropriate morphological identification keys. A total of 22,455 mosquitoes from 89 species, 22 sub species and 11 genera were collected from Arua and Kasese districts. Overall abundance was found to be higher in Kasese (n=13446, 59.9%) than Arua district (n = 9009, 40.1%), though no significant differences were observed across villages in Arua and Kasese districts (Kruskal Wallis, X2 = 2, df = 3, p>0.05). Collection numbers were highest for genus Coquillettidia (n = 7942, 35.4%), followed by Culex (n = 7642, 34.03%), Mansonia (n = 3414, 15.2%), Anopheles (n = 1970, 8.8%) and Aedes (n = 1349, 6.01%). Other species were across 6 genera Eretmopodites (n = 59, 0.26%), Uranoteania (n = 36, 0.16%), Lutzia (n = 26, 0.12%), Mimomyia (n = 13, 0.06%), Aediomyia (n = 3, 0.01%) and Toxorhynchites (n = 1, 0.004%) appeared low in both districts. Species richness was comparatively higher in Kasese than Arua district, however across villages, it was evenly distributed with no significant differences observed, and species diversity was significantly higher in Arua than Kasese (Mann Whitney U test, p<0.05). A number of species identified here have been implied in arbovirus transmission. Moreover, we show the first description of Culex (Culex) litwakae Harbach mosquito in Uganda, a species previously described in the coastal regions of Kenya. The existence of a mosquito species previously not documented in Uganda suggests a likelihood of many invasive species whose potential to transmit viruses to humans and animals remains largely unknown

Economic losses associated with respiratory and helminth infections in domestic pigs in Lira district, Northern Uganda.

This study sought to quantify direct economic losses due to respiratory and gastrointestinal (GI) helminth infections in domestic pigs in Uganda. In a longitudinal study design with repeated measures, farm visits were made at 2 month intervals from October 2018 to September 2019. Weaner and grower pigs (n = 288) aged 2-6  months from 94 farms were sampled. The pigs were monitored for growth and screened for exposure to four important respiratory pathogens: porcine circovirus type 2 (PCV2), porcine reproductive and respiratory syndrome virus (PRRSv), Mycoplasma hyopneumoniae (M. hyo), Actinobacillus pleuropneumoniae (App) using ELISA tests. Farm management practices were recorded and used to generate management level scores. Treatment expenses incurred were recorded throughout the study. A mixed effects model was fitted to quantify effects of respiratory and helminth infections on average daily weight gains (ADGs), with farm and pig as random effects. Analysis of variance (ANOVA) was used to determine differences in mean treatment costs by farm management standard. Financial losses were estimated from average carcass dressing percentage, ADG reductions during fattening (200  days). Results showed a grower pig in a given farm exposed to PRRSv and Ascaris spp. had significantly lower ADG by 17.10 gr/day and 16.80 grams/day respectively, compared to a similar unexposed pig (p < 0.05). Mean treatment costs per pig declined significantly with increase in management standard scores (MSS), from USD 1.13 per pig in MSS 1 (poor management) farms to USD 0.95 for MSS 3 (better management) farms (p < 0.05). We show that monetary losses due to PRRSv and Ascaris spp. infection amounted to USD 6.6 ± 2.7 and 6.50 ± 3.2 (Mean ± SEM) per pig, respectively during 200 days of fattening. This study strengthens evidence that improving management practices to reduce infections mitigates economic losses. To guide interventions, further studies are required to unravel the full extent of indirect economic losses

Descriptive analyses of knowledge, attitudes, and practices regarding rabies transmission and prevention in rural communities near wildlife reserves in Uganda: a One Health cross-sectional study

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The role of African buffalos (syncerus caffer) in the maintenance of foot-and-mouth disease in Uganda

<p>Abstract</p> <p>Background</p> <p>To study the role of African buffalos (<it>Syncerus caffer</it>) in the maintenance of foot-and-mouth disease in Uganda, serum samples were collected from 207 African buffalos, 21 impalas (<it>Aepyceros melampus</it>), 1 giraffe (<it>Giraffa camelopardalis</it>), 1 common eland (<it>Taurotragus oryx</it>), 7 hartebeests (<it>Alcelaphus buselaphus</it>) and 5 waterbucks (<it>Kobus ellipsiprymnus</it>) from four major National Parks in Uganda between 2005 and 2008. Serum samples were screened to detect antibodies against foot-and-mouth disease virus (FMDV) non-structural proteins (NSP) using the Ceditest^®FMDV NS ELISA. Solid Phase Blocking ELISAs (SPBE) were used to determine the serotype-specificity of antibodies against the seven serotypes of FMDV among the positive samples. Virus isolation and sequencing were undertaken to identify circulating viruses and determine relatedness between them.</p> <p>Results</p> <p>Among the buffalo samples tested, 85% (95% CI = 80-90%) were positive for antibodies against FMDV non-structural proteins while one hartebeest sample out of seven (14.3%; 95% CI = -11.6-40.2%) was the only positive from 35 other wildlife samples from a variety of different species. In the buffalo, high serotype-specific antibody titres (≥ 80) were found against serotypes O (7/27 samples), SAT 1 (23/29 samples), SAT 2 (18/32 samples) and SAT 3 (16/30 samples). Among the samples titrated for antibodies against the four serotypes O, SAT 1, SAT 2 and SAT 3, 17/22 (77%; CI = 59.4-94.6%) had high titres against at least two serotypes.</p> <p>FMDV isolates of serotypes SAT 1 (1 sample) and SAT 2 (2 samples) were obtained from buffalo probang samples collected in Queen Elizabeth National Park (QENP) in 2007. Sequence analysis and comparison of VP1 coding sequences showed that the SAT 1 isolate belonged to topotype IV while the SAT 2 isolates belonged to different lineages within the East African topotype X.</p> <p>Conclusions</p> <p>Consistent detection of high antibody titres in buffalos supports the view that African buffalos play an important role in the maintenance of FMDV infection within National Parks in Uganda. Both SAT 1 and SAT 2 viruses were isolated, and serological data indicate that it is also likely that FMDV serotypes O and SAT 3 may be present in the buffalo population. Detailed studies should be undertaken to define further the role of wildlife in the epidemiology of FMDV in East Africa.</p

Molecular Detection of Torque Teno Sus Virus and Coinfection with African Swine Fever Virus in Blood Samples of Pigs from Some Slaughterhouses in Nigeria

Torque teno sus virus 1 (TTSuV1a/TTSuV1b) infection is present in pig herds worldwide. This study investigated the prevalence of TTSuV1a/TTSuV1b infections in domestic pigs from some slaughterhouses in Nigeria as well as coinfection with African swine fever virus (ASFV) and described the phylogeny in relation to global strains. One hundred and eighty-one (181) blood samples from four slaughterhouses were used for the study and viral nucleic acid detection was carried out by PCR. Comparative sequence analysis was carried out to infer phylogeny. The overall prevalence of TTSuV1a/b was 17.7%. Prevalence of individual genotypes was 10.5% and 7.2% for TTSuV1a and TTSuV1b, respectively. Coinfection of ASFV/TTSuV1a/b was 7.7% while that of TTSuV1a and TTSuV1b was 1.7%. ASFV alone was detected in 11.91% of the total samples. The Nigerian TTSuV1a and TTSuV1b shared a sequence identity of 91–100% and 95–100%, respectively, among each other. The ASFV sequences were 100% identical to members of genotype 1. This is the first report on the presence of TTSuV1a/b in domestic pigs in Nigeria and coinfection with ASFV. Although the prevalence of TTSuV1a/b in Nigeria was low, we recommend further studies to establish the trend and possible role in the pathogenesis of ASFV

Application of the Nagoya Protocol to veterinary pathogens: concerns for the control of foot-and-mouth disease

The Nagoya Protocol is an international agreement adopted in 2010 (and entered into force in 2014) which governs access to genetic resources and the fair and equitable sharing of benefits from their utilisation. The agreement aims to prevent misappropriation of genetic resources and, through benefit sharing, create incentives for the conservation and sustainable use of biological diversity. While the equitable sharing of the benefits arising from the utilisation of genetic resources is a widely accepted concept, the way in which the provisions of the Nagoya Protocol are currently being implemented through national access and benefit-sharing legislation places significant logistical challenges on the control of transboundary livestock diseases such as foot-and-mouth disease (FMD). Delays to access FMD virus isolates from the field disrupt the production of new FMD vaccines and other tailored tools for research, surveillance and outbreak control. These concerns were raised within the FMD Reference Laboratory Network and were explored at a recent multistakeholder meeting hosted by the European Commission for the Control of FMD. The aim of this paper is to promote wider awareness of the Nagoya Protocol, and to highlight its impacts on the regular exchange and utilisation of biological materials collected from clinical cases which underpin FMD research activities, and work to develop new epidemiologically relevant vaccines and other diagnostic tools to control the disease

Correlations between lung pneumonic lesions and serologic status for key respiratory pathogens in slaughtered pigs in northern Uganda.

BACKGROUND A cross-sectional study of slaughtered pigs was conducted in Lira district, Uganda, to (1) determine the prevalence and severity of pneumonia and (2) establish relationships between pneumonia types and the serological status for key respiratory pathogens. Using enzyme-linked immunosorbent assays (ELISAs), sera were screened for antibodies against Mycoplasma hyopneumoniae (M. hyo), Actinobacillus pleuropneumoniae (App), porcine reproductive and respiratory syndrome virus (PRRSv) and porcine circovirus type 2 (PCV2). Postmortem, lungs were grossly scored for pneumonia types and pneumonic lesions. Pneumonia types were characterized as catarrhal purulent bronchopneumonia (CPBP), pleuropneumonia (PLP) and pleuritis. The percent of lung surface affected by pneumonia was determined by estimating the affected surface area of each lung lobe. Each lobe was assigned scores based on the approximate volume represented and the total percentage of lung surface affected obtained as a sum of individual lobe scores. Metastrongylus spp. helminth infection was determined by examining lungs for gross presence or absence. RStudio was used for data analysis and presentation. Wilcoxon rank sum tests were used to compare median pneumonia lesion scores and serostatus for each studied pathogen. An ordinal logistic regression model was fitted to evaluate the odds of multiple pneumonia, with pathogen serostatus and Metastrongylus spp. infection as predictors. RESULTS One hundred sixty-seven (n = 167) lungs were examined for pneumonic lesions. The prevalences of CPBP, PLP and pleuritis were 29.9% (95% CI 22.9-36.9), 74.2% (95% CI 67.5-80.9) and 17.3% (95% CI 22.4-36.3), respectively. The true prevalence of PCV2 was 9.7% (95% CI 4.5-16.8), that of PRRSv was 7.5% (95% CI 2.7-14.2), that of M. hyo was 11.5% (95% CI 7.2-18.0), that of App was 25.1% (95% CI 18.5-38.0), and that of Metastrongylus spp. was 29.3% (95% CI 22.9-36.6). The odds of multiple pneumonia forms increased in pigs with multiple pathogens (ORs 2.6, p = 0.01) and Metastrongylus spp. infestation (OR 2.5, p = 0.003), suggesting synergistic effects of coinfections in the induction of lesions. CONCLUSIONS This study revealed a high prevalence and severity of pneumonic lesions in slaughtered pigs. It provides baseline information and evidence for the magnitude of pneumonia associated with the studied pathogens and justifies future studies on their potential economic impacts on Ugandan pigs

Co-infections of respiratory pathogens and gastrointestinal parasites in smallholder pig production systems in Uganda.

A cross-sectional study was conducted to identify factors for infections of pigs with key respiratory pathogens: porcine circovirus type 2 (PCV2), porcine reproductive and respiratory syndrome virus (PPRSv), Mycoplasma hyopneumoniae (M. hyo), Actinobacillus pleuropneumoniae (App), and gastrointestinal (GI) parasites in Uganda. A structured questionnaire was used to collect data on management practices associated with infections. Ninety (90) farms and 259 pigs were sampled. Sera were screened against 4 pathogens using commercial ELISA tests. The Baerman's method was used to identify parasite species in faecal samples. Logistic regression was done to identify risk factors for infections. Results showed individual animal seroprevalence of PCV2 was 6.9% (95% CI 3.7-11.1), PRRSv 13.8% (95% CI 8.8-19.6), M. hyo 6.4% (95% CI 3.5-10.5), and App 30.4% (95% CI 24.8-36.5). The prevalence of Ascaris spp. was 12.7% (95% CI 8.6-16.8), Strongyles spp was 16.2% (95% CI 11.7-20.7), and Eimeria spp. was 56.4% (95% CI 50.3-62.4). Pigs infested with Ascaris spp. were more likely to test positive to PCV2, odds ratio (OR) 1.86 (CI 1.31-2.60; p = 0.0002). For M. hyo, infection with Strongyles spp. was a risk factor (OR 12.9, p < 0.001). Pigs that had Strongyles and Ascaris spp. Infections (ORs 3.5 and 3.4, p < 0.001 respectively) were likely to have co-infections. The model showed that use of cement, elevated floor, and limiting contacts with outside pigs were protective while using mud and helminth infestations increased risks of co-infections. This study provided evidence that improved housing and biosecurity are critical in reducing pathogen incidence in herds

Ecological Niche Modeling for Filoviruses: A Risk Map for Ebola and Marburg Virus Disease Outbreaks in Uganda

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Molecular characterization and phylogenetic study of peste des petits ruminants viruses from North central States of Nigeria

<p>Abstract</p> <p>Background</p> <p>Peste des petits ruminants is an endemic disease of sheep and goats in Nigeria and vaccination has been the method of control but sporadic outbreaks have been reported. This study was carried out to characterize PPR viruses from outbreaks in 2007 and 2009 from Kaduna and Plateau States.</p> <p>Results</p> <p>Of the 33 clinical samples analysed, 51.52% (n = 17) were positive for F protein gene primers (F1/F2). All the samples had a sequence similarity of 98-100% among them and 92-97% with the reference vaccine (Nig 75/1) strain. The deduced amino acid homology ranges between 96.3-99.7%. Phylogenetically all the Nigerian sequences cluster with Nig 75/1 and Nig 76/1 in lineage 1.</p> <p>Conclusions</p> <p>PPR is still a problem in Kaduna and Plateau States of Nigeria. The strains involved were genetically closely related to the vaccine strain (Nig 75/1) used in the country. Based on this study, the continued outbreaks in the Country is not due to the efficacy of the vaccine. Therefore, to achieve effective control and possibly eradication of PPR in Nigeria, the current control strategies should be revisited.</p