Biology subjects

Lindtjorn, B.

Publications and source records attributed to Lindtjorn, B..

4 recordsLinked to original sources

bioRxiv2024

Trypanosome infection rate and blood-feeding patterns of tsetse fly in an area with a recent human African trypanosomiasis outbreak in Southwest Ethiopia

IntroductionThe recent outbreak of Human African Trypanosomiasis (HAT) in the Deme River Valley, Ethiopia, has highlighted the need for more comprehensive data on the infection rate of trypanosomes and the feeding patterns of tsetse. The study aimed to assess the infection rate of trypanosomes and the feeding patterns of tsetse flies collected using various attractants. Methodology/principal findingsTraps with various bait odors were placed randomly and rotated monthly. Anesthetized and recently deceased tsetse flies were examined to determine the infection rate using microscopy, and the origins of the blood meal were determined using the polymerase chain reaction technique. We used the Poisson regression model to analyze count data and the binary logistic regression model to assess binary outcomes (positive or negative) and infection rates. Of the 1208 tsetse flies captured, 751 (62.2%) were Glossina pallidipes, while 457 (37.8%) were Glossina fuscipes fuscipes. The trypanosome infection rate in tsetse flies was 17.1% (95% CI: 14.2-20.3). Of the 103 positive tsetse flies, 66% were infected with T. congolense, 24.3% with T. vivax, 1.9% with T. brucei, and 7.8% with either T. congolense or T. brucei (the immature stages identified in the mid-gut). The infection rate of trypanosomes in G. pallidipes (19. 6%) was higher than that of G. f. fuscipes (12.8%). Traps using a combination of cow urine and acetone captured tsetse flies with a higher infection rate of trypanosomes (21.2%), followed by acetone alone (18.9%), cow urine alone (12.2%), and traps without bait (6.1%). Of 107 freshly fed tsetse flies, 23.4% were fed to dogs, 8.4% to humans, 7.5% to cattle, and 4.7% to goats, including the mixed blood meals. Conclusions/main suggestionsThe high trypanosome infection rate in tsetse flies indicates an increased risk of trypanosomiasis infection. Although tsetse flies seem attracted to dogs, the potential risk of human exposure must also be considered. Further research is needed to understand the role of dogs in parasite transmission. Authors summaryAfrican Animal Trypanosomosis (AAT) is a significant issue in animal production in sub-Saharan African countries, including Ethiopia. The recent outbreak of HAT in the Deme River Valley, Ethiopia, has emphasized the need for more comprehensive data on the infection rate of trypanosomes and the feeding patterns of tsetse flies to understand human exposure. The current study revealed a high infection rate of trypanosomes in tsetse flies, with T. congolense having the highest prevalence, followed by T. vivax. Public concern is related to the T. brucei complex, as it is possibly the strain that causes HAT. Combining cow urine with acetone could significantly improve tsetse trapping and be used in tsetse suppression programs to reduce the risks of infectious tsetse flies. Analysis of the blood meal origins revealed that tsetse flies feed on various vertebrate animals, including dogs and humans. Urgent research is needed to understand the role of dogs in parasite transmission. It is recommended that large-scale tsetse control be implemented using baits such as fermented cow urine in combination with acetone for tsetse suppression.

zoology↗

bioRxiv2019

Intestinal parasites among rural schoolchildren in southern Ethiopia: A cross-sectional multilevel and zero-inflated regression model

BackgroundOver 28 million school-aged children are at risk of intestinal parasite infection in Ethiopia. Few studies have investigated household-level risk factors or applied multilevel analysis to account for the nested data structure. This study aimed to assess the prevalence, intensity, and risk factors of parasite infection among schoolchildren in rural South Ethiopia. Methodology/Principal FindingsUsing multistage random sampling, we recruited 864 students in the Wonago district. We applied multilevel-logistic and zero-inflated negative binomial regression models (ZINB). Risk factors were concentrated at the individual level; school-level and class-level variables explained less than 5% of the variance. The overall intestinal parasite prevalence was 56% (479/850); Trichuris trichiura prevalence was 75.2% (360/479); and Ascaris lumbricoides prevalence was 33.2% (159/479). The rate of infection increased among children with anemia (AOR: 1.45 [95% CI: 1.04, 2.03]), wasting (AOR: 1.73 [95% CI: (1.04, 2.90]), mothers who had no formal education (AOR: 1.08 [95% CI: 1.25, 3.47]), and those in households using open containers for water storage (AOR: 2.06 [95% CI: 1.07, 3.99]). In the ZINB model, A. lumbricoides infection intensity increased with increasing age (AOR: 1.08 [95% CI: 1.01, 1.16]) and unclean fingernails (AOR: 1.47 [95% CI: 1.07, 2.03]). Handwashing with soap (AOR: 0.68 [95% CI: 0.48, 0.95]), de-worming treatment [AOR: 0.57 (95% CI: 0.33, 0.98)], and using water from protected sources [AOR: 0.46 (95% CI: 0.28, 0.77)] were found to be protective against parasitic infection. Conclusions/SignificanceAfter controlling for clustering effects at the school and class levels and accounting for excess zeros in fecal egg counts, we found an association between parasite infections and the following variables: age, wasting, anemia, unclean fingernails, handwashing, de-worming treatment, mothers education, household water source, and water storage protection. Improving hygiene behavior, providing safe water at school and home, and strengthening de-worming programs is required to improve the health of schoolchildren in rural Gedeo. Author summaryIntestinal parasite infections are common among school-aged children in Ethiopia. Several cross-sectional studies have investigated the prevalence and risk factors of these intestinal parasite infections. However, most were conducted in an urban setting in northern Ethiopia; they collected household-level risk factor information from the children, not the parents; and they restricted intestinal parasite infection data to binary outcomes. Therefore, we aimed to assess the prevalence and intensity of intestinal parasite infections and the related individual-, household-, and school-level risk factors among rural schoolchildren in southern Ethiopia. Using a multivariate, multilevel, regression model, we found minimal variation across class- and school-level factors for intestinal parasite infection prevalence. We found associations between intestinal parasite infections and most individual-level factors and some household-level factors. Therefore, interventions focusing on the individual, household, and school should be implemented to reduce the prevalence of infection and parasite load among schoolchildren.

microbiology↗

bioRxiv2019

Feeding behavior and activity of Phlebotomus pedifer and potential reservoir hosts of Leishmania aethiopica in southwestern Ethiopia.

BackgroundCutaneous leishmaniasis (CL) is a major public health concern in Ethiopia. However, knowledge about the complex zoonotic transmission cycle is limited, hampering implementation of control strategies. We explored the feeding behavior and activity of the vector (Phlebotomus pedifer) and established the role of livestock in CL transmission. MethodsBlood meal origins of engorged sand flies were determined by sequencing host DNA. A host choice experiment was performed to assess the feeding preference of P. pedifer when humans and hyraxes are equally accessible. Ear and nose biopsies from goats and bovines were screened for the presence of Leishmania parasites. Sand flies were captured indoor and outdoor with human landing catches (HLC) and CDC light traps to determine at which time and where P. pedifer is mostly active. Principal findingsA total of 180 sand flies were found to bite hosts of 12 genera. Humans were the predominant blood meal source (59.4%, p < 0.001) in all habitats, even in caves, where hyraxes are abundant. Only 10.6% of the sand flies fed on hyraxes based on the blood meal analysis, but the host choice experiment revealed that sand flies have a significant preference for feeding on hyraxes over humans (p = 0.009) when hosts are equally accessible. Only a single goat nose biopsy from 412 animal samples was found with Leishmania RNA. We found that P. pedifer is predominantly endophagic (p = 0.003), but occurs both indoors and outdoors. A substantial amount of sand flies was active in the early evening, which increased over time reaching its maximum around midnight. ConclusionWe indicate that Leishmania transmission in southwestern Ethiopia is, in contrast to earlier suggestions, likely mainly anthroponotic and that livestock does not play a role in transmission. Combined indoor and outdoor vector control measures at night are required for efficient vector control. Author summaryCutaneous leishmaniasis is a major public health problem in Ethiopia. It is caused by Leishmania aethiopica protozoa that are transmitted when female sand flies take a blood meal. Hyraxes are assigned as the reservoirs of the infection, because many were found infected with Leishmania. There is very limited knowledge about the behavior of sand flies and other potential hosts of the infection. However, this information is a prerequisite for disease control, which is currently hampered. In this study, we found that humans are likely the main source of the infection and that the role of hyraxes in disease transmission needs further investigation to decide whether they should be included in control programs. Livestock appears not play a role in transmission, even though sand flies like to feed on them. We also show that sand flies are active indoors and outdoors, but have a preference for feeding inside human dwellings and that they are mostly active around midnight. Overall, we conclude that disease prevention and control should emphasize on human protection by applying vector control indoors, at night.

ecology↗

bioRxiv2019

Health service utilisation lags behind maternal diseases or illnesses during pregnancy in rural south Ethiopia: A prospective cohort study

Maternal survival has improved substantially in the last decades, but evidence on maternal morbidity and health service utilisation for various maternal diseases are scarce in low resource settings. We aimed to measure health service utilisation for maternal illnesses during pregnancy. A cohort study of 794 pregnant women in rural southern Ethiopia was carried-out from May 2017 to July 2018. Disease or illness identification criteria were: symptoms, signs, physical examination, and screening of anaemia. Follow-up was done every two weeks. Data on health service utilisation was obtained from women and confirmed by visiting the health facility. Multilevel, multiple responses, repeated measures, and generalized linear mixed model analysis were used. The cumulative incidence of women experiencing illness episodes was 91%, and there were 1.7 episodes of diseases or illnesses per woman. About 22% of pregnant women were anaemic and 8% hypertensive. Fourteen pregnant women experienced abortions, 6 had vaginal bleeding, 48% pain in the pelvic area, 4% oedema, and 72% tiredness. However, health service utilisation was only 7%. About 94% of anaemic women did not get iron-folic-acid tablet supplementation. Only two mothers with blurred vision and severe headache were referred for further treatment. The main reasons for not using the health services were: the perception that symptoms would heal by themselves (47%), illness to be minor (42%), financial constraints (10%), and lack of trust in health institutions (1%). Risk factors were being older women, poor, having a history of abortion, living far away from the health institution, travelled longer time to reach a health institution, and monthly household expenditure >=30 USD. In Conclusion, there was a high incidence of diseases or illnesses; however health service utilisation was low. Poor understanding of severe and non-severe symptoms was an important reason for low health service utilisation. Therefore, community-based maternal diseases or illness survey could help for early detection. Ministry of Health should promote health education that encourages women to seek appropriate and timely care.

epidemiology↗