scholarly journals Spatio-temporal distribution of Spiroplasma infections in the tsetse fly (Glossina fuscipes fuscipes) in northern Uganda

2019 ◽  
Author(s):  
Daniela I. Schneider ◽  
Norah Saarman ◽  
Maria G. Onyango ◽  
Chaz Hyseni ◽  
Robert Opiro ◽  
...  
Keyword(s):  
Genetic Background ◽  
Linear Models ◽  
Geographic Origin ◽  
Transmission Efficiency ◽  
Tsetse Fly ◽  
Sub Saharan Africa ◽  
Trypanosome Infection ◽  
Glossina Fuscipes Fuscipes ◽  
Sub Saharan ◽  
Western Uganda

AbstractTsetse flies (Glossina spp.) are vectors of parasitic trypanosomes, which cause human (HAT) and animal African trypanosomiasis (AAT) in sub-Saharan Africa. In Uganda, Glossina fuscipes fuscipes (Gff) is the main vector of HAT, where it transmits Gambiense disease in the northwest and Rhodesiense disease in central, southeast and western regions. Endosymbionts can influence transmission efficiency of parasites through their insect vectors via conferring a protective effect against the parasite. It is known that the bacterium Spiroplasma is capable of protecting its Drosophila host from infection with a parasitic nematode. This endosymbiont can also impact its host’s population structure via altering host reproductive traits. Here, we used field collections across 26 different Gff sampling sites in northern and western Uganda to investigate the association of Spiroplasma with geographic origin, seasonal conditions, Gff genetic background and sex, and trypanosome infection status. We also investigated the influence of Spiroplasma on Gff vector competence to trypanosome infections under laboratory conditions.Generalized linear models (GLM) showed that Spiroplasma probability was correlated with the geographic origin of Gff host and with the season of collection, with higher prevalence found in flies within the Albert Nile (0.42 vs 0.16) and Achwa River (0.36 vs 0.08) watersheds and with higher prevalence detected in flies collected in the intermediate than wet season. In contrast, there was no significant correlation of Spiroplasma prevalence with Gff host genetic background or sex once geographic origin was accounted for in generalized linear models. Additionally, we found a potential negative correlation of Spiroplasma with trypanosome infection, with only 2% of Spiroplasma infected flies harboring trypanosome co-infections. We also found that in a laboratory line of Gff, parasitic trypanosomes are less likely to colonize the midgut in individuals that harbor Spiroplasma infection. These results indicate that Spiroplasma infections in tsetse may be maintained by not only maternal but also via horizontal transmission routes, and Spiroplasma infections may also have important effects on trypanosome transmission efficiency of the host tsetse. Potential functional effects of Spiroplasma infection in Gff could have impacts on vector control approaches to reduce trypanosome infections.Author SummaryWe investigated the association of symbiotic Spiroplasma with the tsetse fly host Glossina fuscipes fuscipes (Gff) to assess if Spiroplasma infections are correlated with Gff genetic background, geography, or season and its interaction with trypanosome parasites. We analyzed distribution and prevalence of Spiroplasma infections across different Gff sampling sites in northern and western Uganda, and found that the symbiont is unevenly distributed and infections have not reached fixation within these sampling sites. We tested for associations with geographic origin of the collections, seasonal environmental conditions at the time of collection, Gff host genetic background and sex, plus trypanosome co-infections. Spiroplasma prevalence was strongly correlated with geographic origin and seasonal environmental conditions. Our parasite infection data suggested a negative correlation of Spiroplasma with trypanosome infection, with only 5 out of 243 flies harboring trypanosome co-infections. We further investigated the influence of Spiroplasma on trypanosome parasite infections in the laboratory. We found that trypanosomes were less likely to establish an infection in Gff individuals that carried Spiroplasma infections. Our results provide new information on host-endosymbiont dynamics in an important human disease vector, and provide evidence that Spiroplasma may confer partial resistance to Gff trypanosome infections. These findings provide preliminary evidence that a symbiont-based control method could be successful in combating tsetse trypanosome transmission to humans and livestock in sub-Saharan Africa.

Distribution of tsetse flies and its Trypanosoma species infection in Old Oyo National Park, Nigeria

2021 ◽  
Vol 18 (1) ◽  
pp. 33-38
Author(s):  
A.O. Omonona ◽  
S.A. Abioye ◽  
P.O. Odeniran ◽  
I.O. Ademola
Keyword(s):  
National Parks ◽  
National Park ◽  
Ground Level ◽  
Tsetse Fly ◽  
Sub Saharan Africa ◽  
Tsetse Flies ◽  
Trypanosome Infection ◽  
Wet Season ◽  
Significant Difference ◽  
Sub Saharan

Tsetse fly infestation in national parks is a major health risk to both the wildlife and tourists coming to sub-Saharan Africa. However, information on distribution and diversity of tsetse flies and trypanosome infection rate in Protected Areas like Old Oyo National Park in south-west Nigeria is largely unknown. Thus, the study evaluates distribution and diversity of tsetse flies in Magurba Range of Old Oyo National Park. Twelve Nzi traps were set at 50 m equidistance to capture Glossina species for a period of six months between February and August, 2019, considering both the altitudinal and ecological significance. A total of 136 tsetse flies belonging to four species; G. palpalis, G. tachinoides, G. morsitans and G. fusca; were captured. More Glossina species were captured during dry season 77.9% (70.0-84.6) than the wet season 22.1% (15.4-30.0). There was significant difference (p = 0.0001; x2 = 84.9; OR = 12.5) between the proportion of Glossina species captured at the riverine areas (106; 77.9%) and the woodland/forest areas (30; 22.1%). Glossina captured at ground level and 30 cm above ground were 71 (52.2 %) and 65 (47.8%) respectively. The overall prevalence of trypanosome infection (2.94%) was observed for Glossina spp. The presence of infected Glossina spp. indicated an urgent need to establish a concise strategic vector control in National Parks, in order to reduce the risk of transmission to both wildlife and humans in the area. The park is frequently visited by tourists, rangers, researchers and students for educational purposes. Keywords: Glossina spp.; Trypanosoma spp.; vector distribution; Old Oyo National Park

scholarly journals Local responses to a forest park in western Uganda: alternate narratives on fortress conservation

Oryx ◽  
2010 ◽  
Vol 45 (1) ◽  
pp. 60-68 ◽  
Author(s):  
Joel Hartter ◽  
Abraham Goldman
Keyword(s):  
Sub Saharan Africa ◽  
Large Majority ◽  
External Control ◽  
Economic Returns ◽  
Forest Park ◽  
Local Responses ◽  
Sub Saharan ◽  
Negative Impacts ◽  
Forest Parks ◽  
Western Uganda

AbstractMost research on attitudes to parks in sub-Saharan Africa has been in savannah regions and areas of low population density. Expulsion, exclusion and the imposition of external control are dominant themes, resulting in negative responses to parks, particularly those that represent hard-edged so-called fortress conservation. Our research in the densely populated area around a mid altitude forest park in western Uganda found an alternate narrative in which, despite its hard-edged fortress features, most people view Kibale National Park favourably. Based on a geographically random sample in two agricultural areas neighbouring the Park, our results indicate that most households felt they benefit from the Park and only a small proportion cited negative impacts. Rather than direct economic returns, the benefits most commonly noted by respondents can be characterized as ecosystem services. Most individual respondents and a large majority of the local political leaders said that the Park should continue to exist. Crop raiding by animals from the Park is a problem in some locations but resource restrictions and expulsion were not widely cited by our respondents. The fact that the large majority of residents migrated to the area after the Park was established may be an important explanatory factor for these responses, and this is also likely to be the case for many other mid altitude tropical forest parks, the demographic and land-use histories of which differ from those around many savannah parks.

scholarly journals Tsetse fly distribution and occurrence of Trypanosoma species among cattle and goats around Queen Elizabeth National park, Uganda

2020 ◽  
Author(s):  
Mallion Kangume ◽  
Denis Muhangi ◽  
Joseph Byaruhanga ◽  
Aggrey Agaba ◽  
Joachim Sserunkuma ◽  
...  
Keyword(s):  
Mixed Infection ◽  
National Park ◽  
Glossina Pallidipes ◽  
Tsetse Fly ◽  
Sub Saharan Africa ◽  
Public Health Importance ◽  
Baseline Information ◽  
Sub Saharan ◽  
Animal Trypanosomiasis ◽  
And Control

Abstract Background African Animal Trypanosomiasis (AAT) is an infectious disease of economic and public health importance hindering agricultural productivity in Sub-Saharan Africa. The current study aimed at providing baseline information on tsetse fly distribution and occurrence of Trypanosoma species in cattle and goats within and around Queen Elizabeth National Park (QENP), in western Uganda. A minimal entomological survey was conducted in April 2017 while blood samples collected from cattle (n = 576) and goats (n = 319) in June 2015 and May 2017 were subjected to microscopy and Polymerase Chain Reaction (PCR) to determine the occurrence of trypanosome species. Results Glossina pallidipes and G. fuscipes were the only tsetse fly species trapped in the study area with apparent density of 20.6. The overall prevalence of Trypanosoma spp. in cattle and goats was 38.9% and 37% respectively for samples collected in 2015 while the prevalence of Trypanosome spp in cattle samples collected in 2017 was 38%. In 2015, T. brucei was the highest prevalent trypanosome in both cattle (23%) and goats (18.8%). In both cattle and goats, a mixed infection of T. brucei + T. congolense was most encountered with prevalence of 4.8% and 4.1% in cattle and goats, respectively. In goats a mixed infection of T. brucei + T. congolense + T. vivax was higher (2.8%) than in cattle (2.4%). In 2017, in cattle (n = 250), the prevalence for T. congolense was 32.4%, T. vivax was 6.8% and T. brucei was 6.4%. A co-infection of T. brucei and T. congolense was most prevalent (7.4%). Only 3.2% of the cattle were co-infected with all the three Trypanosome species. Conclusions Current findings show that there are two types of Tsetse fly specie, s important in transmission of AAT. Presence of these parasites in goats shows that they also play a key role in epidemiology of the disease and control efforts should aim also involve goat farmers.

Increase in clinical prevalence of AIDS implies increase in unsafe medical injections

2009 ◽  
Vol 20 (5) ◽  
pp. 295-299 ◽  
Author(s):  
S Reid
Keyword(s):  
Hiv Infections ◽  
Transmission Efficiency ◽  
Mass Action ◽  
Sub Saharan Africa ◽  
World Health ◽  
Sub Saharan ◽  
Exposure Risks ◽  
Health Organization ◽  
A Minor ◽  
Advanced Hiv Disease

A mass action model developed by the World Health Organization (WHO) estimates that the re-use of contaminated syringes for medical care accounted for 2.5% of HIV infections in sub-Saharan Africa in 2000. The WHO's model applies the population prevalence of HIV infection rather than the clinical prevalence to calculate patients' frequency of exposure to contaminated injections. This approach underestimates iatrogenic exposure risks when progression to advanced HIV disease is widespread. This sensitivity analysis applies the clinical prevalence of HIV to the model and re-evaluates the transmission efficiency of HIV in injections. These adjustments show that no less than 12–17%, and up to 34–47%, of new HIV infections in sub-Saharan Africa may be attributed to medical injections. The present estimates undermine persistent claims that injection safety improvements would have only a minor impact on HIV incidence in Africa.

The poverty alleviation potential of tourism employment as an off-farm activity on the local livelihoods surrounding Kibale National Park, western Uganda

2016 ◽  
Vol 17 (1) ◽  
pp. 34-51 ◽  
Author(s):  
Bright Adiyia ◽  
Dominique Vanneste ◽  
Anton Van Rompaey
Keyword(s):  
National Park ◽  
Livelihood Strategies ◽  
Kibale National Park ◽  
Sub Saharan Africa ◽  
Farm Income ◽  
Continuous Growth ◽  
Household Level ◽  
Local Livelihoods ◽  
Sub Saharan ◽  
Western Uganda

Over the past decade, several scholars have argued that livelihood diversification in terms of off-farm activities is key for rural households to escape from poverty in Sub-Saharan Africa (SSA). Although the continuous growth of tourism in many SSA countries has created an additional off-farm income activity, empirical evidence is lacking to substantiate the poverty alleviating impact of tourism employment as being consistent and universal at the household level. Using the case of Kibale National Park in western Uganda, the aims of this paper are (1) to analyze the actual income composition of different types of rural livelihood strategies by means of cluster analysis, and (2) to compare the financial impact of tourism employment with alternative off-farm income activities. Results show a large differentiation in income compositions of households around Kibale National Park. In general, households engaged in off-farm income activities have higher levels of overall household welfare. Tourism employment generates low incomes compared to alternative off-farm activities, but still enables households to strengthen livelihood strategies by investments in on-farm or alternative off-farm activities.

scholarly journals In Vitro, Ex Vivo, and In Vivo Activities of Diamidines against Trypanosoma congolense and Trypanosoma vivax

2017 ◽  
Vol 61 (5) ◽  
Author(s):  
Kirsten Gillingwater ◽  
Christina Kunz ◽  
Christiane Braghiroli ◽  
David W. Boykin ◽  
Richard R. Tidwell ◽  
...  
Keyword(s):  
Ex Vivo ◽  
Trypanosoma Congolense ◽  
Tsetse Fly ◽  
Sub Saharan Africa ◽  
Content Type ◽  
Lead Compounds ◽  
Single Bolus Dose ◽  
Sub Saharan

ABSTRACT African animal trypanosomosis (AAT) is caused by the tsetse fly-transmitted protozoans Trypanosoma congolense and T. vivax and leads to huge agricultural losses throughout sub-Saharan Africa. Three drugs are available to treat nagana in cattle (diminazene diaceturate, homidium chloride, and isometamidium chloride). With increasing reports of drug-resistant populations, new molecules should be investigated as potential candidates to combat nagana. Dicationic compounds have been demonstrated to have excellent efficacy against different kinetoplastid parasites. This study therefore evaluated the activities of 37 diamidines, using in vitro and ex vivo drug sensitivity assays. The 50% inhibitory concentrations obtained ranged from 0.007 to 0.562 μg/ml for T. congolense and from 0.019 to 0.607 μg/ml for T. vivax. On the basis of these promising results, 33 of these diamidines were further examined using in vivo mouse models of infection. Minimal curative doses of 1.25 mg/kg of body weight for both T. congolense- and T. vivax-infected mice were seen when the diamidines were administered intraperitoneally (i.p.) over 4 consecutive days. From these observations, 15 of these 33 diamidines were then further tested in vivo, using a single bolus dose for administration. The total cure of mice infected with T. congolense and T. vivax was seen with single i.p. doses of 5 and 2.5 mg/kg, respectively. This study identified a selection of diamidines which could be considered lead compounds for the treatment of nagana.

scholarly journals Tsetse and trypanosomosis in Africa : the challenges, the opportunities : vector-borne diseases : trypanosomosis

2009 ◽  
Vol 76 (1) ◽  
Author(s):  
A.A. Ilemobade
Keyword(s):  
Disease Burden ◽  
Agricultural Productivity ◽  
Tsetse Fly ◽  
Sub Saharan Africa ◽  
African Continent ◽  
Land Area ◽  
Vector Borne Diseases ◽  
Vector Borne ◽  
Sub Saharan ◽  
The Impact

Tsetse-fly and the disease it transmits, trypanosomosis, remain an enormous disease challenge in the 37 countries of sub-Saharan Africa where the impact continues to be manifest in disease burden, increased level of poverty and decreased agricultural productivity. The impact also extends over an estimated 10 million km2 (a third of the African continent) of land area, a third of which contains some well-watered part of the continent, thus denying humans and livestock of potentially rich arable and pastureland.

scholarly journals Strains used in whole organism Plasmodium falciparum vaccine trials differ in genome structure, sequence, and immunogenic potential

2020 ◽  
Vol 12 (1) ◽  
Author(s):  
Kara A. Moser ◽  
Elliott F. Drábek ◽  
Ankit Dwivedi ◽  
Emily M. Stucke ◽  
Jonathan Crabtree ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Vaccine Efficacy ◽  
De Novo ◽  
Genome Structure ◽  
Geographic Origin ◽  
Cell Epitope ◽  
Sub Saharan Africa ◽  
Clinical Isolates ◽  
Sub Saharan ◽  
Sequencing Platforms

Abstract Background Plasmodium falciparum (Pf) whole-organism sporozoite vaccines have been shown to provide significant protection against controlled human malaria infection (CHMI) in clinical trials. Initial CHMI studies showed significantly higher durable protection against homologous than heterologous strains, suggesting the presence of strain-specific vaccine-induced protection. However, interpretation of these results and understanding of their relevance to vaccine efficacy have been hampered by the lack of knowledge on genetic differences between vaccine and CHMI strains, and how these strains are related to parasites in malaria endemic regions. Methods Whole genome sequencing using long-read (Pacific Biosciences) and short-read (Illumina) sequencing platforms was conducted to generate de novo genome assemblies for the vaccine strain, NF54, and for strains used in heterologous CHMI (7G8 from Brazil, NF166.C8 from Guinea, and NF135.C10 from Cambodia). The assemblies were used to characterize sequences in each strain relative to the reference 3D7 (a clone of NF54) genome. Strains were compared to each other and to a collection of clinical isolates (sequenced as part of this study or from public repositories) from South America, sub-Saharan Africa, and Southeast Asia. Results While few variants were detected between 3D7 and NF54, we identified tens of thousands of variants between NF54 and the three heterologous strains. These variants include SNPs, indels, and small structural variants that fall in regulatory and immunologically important regions, including transcription factors (such as PfAP2-L and PfAP2-G) and pre-erythrocytic antigens that may be key for sporozoite vaccine-induced protection. Additionally, these variants directly contributed to diversity in immunologically important regions of the genomes as detected through in silico CD8+ T cell epitope predictions. Of all heterologous strains, NF135.C10 had the highest number of unique predicted epitope sequences when compared to NF54. Comparison to global clinical isolates revealed that these four strains are representative of their geographic origin despite long-term culture adaptation; of note, NF135.C10 is from an admixed population, and not part of recently formed subpopulations resistant to artemisinin-based therapies present in the Greater Mekong Sub-region. Conclusions These results will assist in the interpretation of vaccine efficacy of whole-organism vaccines against homologous and heterologous CHMI.

scholarly journals Dengue in western Uganda: A prospective cohort of children presenting with undifferentiated febrile illness

2020 ◽  
Author(s):  
Ross M. Boyce ◽  
Matthew Collins ◽  
Rabbison Muhindo ◽  
Regina Nakakande ◽  
Emily J Ciccone ◽  
...  
Keyword(s):  
Rapid Test ◽  
Febrile Illness ◽  
Sub Saharan Africa ◽  
Urban Site ◽  
Igg Antibodies ◽  
Rt Pcr ◽  
Elisa Testing ◽  
Sub Saharan ◽  
Western Uganda ◽  
Ecological Suitability

Background: The spatial distribution and burden of dengue in sub-Saharan Africa remains highly uncertain, despite high levels of ecological suitability. The goal of this study was to describe the epidemiology of dengue among a cohort of febrile children presenting to outpatient facilities located in areas of western Uganda with differing levels of urbanicity and malaria transmission intensity. Methods: Eligible children were first screened for malaria using rapid diagnostic tests. Children with a negative malaria result were tested for dengue using a combination NS1/IgM/IgG rapid test (SD Bioline Dengue Duo). Confirmatory testing by RT-PCR was performed in a subset of participants. Antigen-capture ELISA was performed to estimate seroprevalence. Results: Only 6 of 1,416 (0.42%) children had a positive dengue rapid test, while none of the RT-PCR results were positive. ELISA testing demonstrated reactive IgG antibodies in 28 (2.2%) participants with the highest prevalence seen at the urban site in Mbarara (19 of 392, 4.9%, p<0.001). Conclusions: Overall, these findings suggest that dengue, while present, is an uncommon cause of non-malarial, pediatric febrile illness in western Uganda. Further investigation into the eocological factors that sustain low-level transmission in urban settings are urgently needed to reduce the risk of epidemics.

scholarly journals Tsetse fly distribution and occurrence of Trypanosoma species among cattle and goats around Queen Elizabeth National park, Uganda

2020 ◽  
Author(s):  
Mallion Kangume ◽  
Denis Muhangi ◽  
Joseph Byaruhanga ◽  
Aggrey Agaba ◽  
Joachim Sserunkuma ◽  
...  
Keyword(s):  
National Park ◽  
Glossina Pallidipes ◽  
Dual Infection ◽  
Tsetse Fly ◽  
Sub Saharan Africa ◽  
Tsetse Flies ◽  
Baseline Information ◽  
Veterinary Importance ◽  
Sub Saharan ◽  
Animal Trypanosomiasis

Abstract Background: African Animal Trypanosomiasis (AAT) is an infectious disease of economic and veterinary importance in Sub-Saharan Africa. The current study aimed at providing baseline information on tsetse fly distribution and occurrence of Trypanosoma species in cattle and goats within and around Queen Elizabeth National Park (QENP), in western Uganda. A minimal entomological survey was conducted in April 2017 while blood samples collected from cattle (n = 576) and goats (n = 319) in June 2015 and May 2017 were subjected to Polymerase Chain Reaction (PCR) to determine the occurrence of Trypanosoma species.Results: Glossina pallidipes and G. fuscipes were the only tsetse fly species trapped in the study area with apparent density of 20.6. The overall prevalence of Trypanosoma spp. was 27% for goats and approximately 38% for cattle. The most prevalent Trypanosoma spp. in goats was T. brucei (n = 60, 18.8%) while the most prevalent in cattle was T. congolense (n = 102, 27.1%). In both cattle and goats, a dual infection of T. brucei + T. congolense was most encountered. In goats a triple infection of T. brucei + T. congolense + T. vivax was higher than that in cattle. Conclusions: Current findings show that there are two species of tsetse flies, and three species of Trypanosoma, important in transmission of AAT in both cattle and goats. Control efforts of AAT have mainly focused on cattle and this study proves that prevention and control efforts should also involve goat farmers.

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