Jahashi Nzalawahe

Background: Rodents and shrews are linked to the transmission of pathogens through arthropod vectors. Purpose: This study determined the prevalence of ectoparasites in rodents and shrews associated with host species, habitat, and seasonality in Mgeta, Morogoro Region, Tanzania. Method: Using a cross sectional design, Sherman and wire traps captured rodents and shrews over six months across two seasons (wet and dry) in three habitats: households, farms, and forests stratified by elevation (low and high). Ectoparasites were processed, identified, and quantified. Results: A total of 200 rodents and shrews representing eight species: Montemys delectorum, Mastomys natalensis, Lophuromys machangui, Rattus rattus, Grammomys doilichurus, Crocidura sp., Otomys angoniensis and Mus musculus. The overall ectoparasite prevalence was 62.5%. The highest prevalence was of mites (50%, Laelaps sp.), followed by fleas (25%: Dinopsyllus spp. 19%, Ctenopthalmus spp. 3%, Xenopsylla brasiliensis 2.5%) and ticks (Haemaphysalis spp., 2.5%). Low forest habitat had the highest ectoparasite prevalence (19.5%), followed by high farm (18.5%), low farm (13%), high forest (8%) and indoor (3.5%). Habitat significantly influenced overall ectoparasite and mite prevalence. The dry season had a higher ectoparasite prevalence (43.5%) than the wet season (19%). Seasonality influenced flea and mite prevalence. Conclusion: The high prevalence of public health significant ectoparasites in rodents and shrews highlights disease transmission risks. Monitoring parasitic assemblages is imperative for disease control.

Background: The emergence of a zoonotic disease pathogen in humans commonly reflects their exposure to mammalian wildlife, such as bats. Bats are significant bacteria reservoir responsible for both pathogens’ transmission and environmental contamination. However, despite their potential, few studies in Tanzania have used metagenomic tools to characterize zoonotic bacterial profiles from animals, thus highlighting a critical gap in regional microbial surveillance efforts. Purpose: This study sought to utilize nanopore sequencing platforms in the detection of microbiome in tissue collected from bats within the Bunduki ecosystem. Method: A cross-sectional study was conducted from January to March 2024. Bats were live-trapped using mist-net from undisturbed forests. DNA was extracted directly from pooled tissue samples using DNeasy Blood and Tissue Kit (cat. No. 69506) and the library for nanopore next-generation sequencing was prepared using the Rapid PCR Barcoding Kit 24 V14 (Oxford Nanopore Technologies), we used ONT Guppy v6.4.2 with the 9.4.1 450 bps SUP model for base calling from the MinION sequencing data and the data were run in CZ ID for a metagenomic overview. Results: A total of 30 live bats were captured, a pooled sample uncovered several microbial taxa; those with opportunistic properties include Leclercia adecarboxylata; of environmental properties include Cupriavidus basilensis, Cupriavidus nantongensis, Cupriavidus oxalaticus, Emticicia oligotrophica; that of plants, Ralstonia pseudosolanacearum; and Bacteriophages, Escherichia phage DW-EC. Such findings increase the value of bat microbiota at the human–animal–environment interface. Conclusion: These results provide baseline data for microbial surveillance in Tanzania. Although there are pooling limitations, this work highlights the importance of the integration of metagenomics into One Health approaches for early detection and control of zoonotic menace, especially in areas with high interaction between wildlife and humans.

Background: In East Africa, bovine schistosomiasis, although common, is poorly appreciated and managed, detrimentally impacting upon livestock health. In certain settings, bovine schistosomiasis may be involved in zoonotic transmission of human schistosomiasis. Better disease management and more effective control of bovine schistosomiasis require the development of sensitive and specific serological screening and rapid diagnostic tools. Methods: We developed an enzyme-linked immunosorbent assay (ELISA) for Schistosoma bovis detection in cattle, utilizing nine shortlisted potential diagnostic protein targets. These shortlisted candidates, STI, IPP, OP, PGK1, COG, PDZ, and Sbp80 (as three fragments), were identified from Schistosoma japonicum homologs already reported with the highest diagnostic potential. In S. bovis, these proteins participate in various biological processes, including metabolic pathways, transcriptional regulation, glycolysis, phosphorylation, and cell signalling, although their real diagnostic potential has not been explored until now. Results: The ELISA was optimized using bovine blood serum samples from regions in Tanzania and validated for sensitivity and specificity. Two targets of specific focus, Conserved Oligomerix Golgi complex subunit 4 (COG) and a domain of the cysteine protease calpain (Sbp80), achieved the highest specificity and sensitivity among the recombinant proteins, with 92% and 88% sensitivity and 100% and 80% specificity, respectively. We further evaluated the COG-based and calpain-based ELISA on further “real-world” bovine serum samples from abattoir sites in Zanzibar, detecting S. bovis in 59.1% of tested animals. Conclusions: Both COG and calpain are promising candidates for serological screening and later inclusion in portable diagnostic tests for S. bovis infection in cattle. Such future diagnostic assays will enable better point-of-detection monitoring, and once scalable, aid in the control of disease in cattle. Graphical

Sandflies are dipterans of medical significance, well-known for transmitting Leishmania parasite. This study investigated the occurrence, composition and distribution of sandflies. Sandflies were collected for three consecutive nights each week at each sampling point using CDC miniature light traps, sticky traps and manual aspiration. Captured sandflies were morphologically identified, based on head structure and terminalia, following standard keys. A generalised linear model was used to determine the effects of explanatory variables on sandfly abundance. Shannon-wiener and Jaccard’s similarity indices were utilised to calculate species diversity and community similarity, respectively. A total of 586 Phlebotomine sandflies were collected, comprising eight species; Sergentomyia freetownensis (38.74%), Se. antennata (49.49%), Se. schwetzi (4.61%), Se. bedfordi (3.75%), Se. adleri (1.19%), Grassomyia squamipleuris (0.68%), Phlebotomus martini (0.85%) and Ph. vansomerenae (0.68%). Sandfly abundance was significantly influenced by habitat type ( X ² = 71.6, df = 2, P < 0.001), altitudinal range ( X ² = 46.85, df = 2, P < 0.001), average temperature ( X ² = 39.16, df = 1, P < 0.001) and average relative humidity ( X ² = 41.03, df = 1, P < 0.001). Sandfly diversity was higher in farmland (H’ = 1.149) and at mid-altitude areas (H’ = 1.079). The presence of competent and susceptible vectors species in the study villages underscores the necessity for surveillance, including vectorial capacity and bloodmeal sources as fundamental factors in incriminating the vector in areas considered non-endemic.

Fleas are important vectors of numerous pathogens, including bacteria, viruses, helminths and protozoa, and their abundance on small mammals may be influenced by various biotic and abiotic factors. This study investigated the associations between gastrointestinal helminth infections, selected haematological parameters and flea abundance in small mammals from three selected districts of Tanzania. Two wards and two villages within each district were purposively selected for sampling in Mbulu, Lushoto and Morogoro District Council. Small mammals were captured from households, fallow lands, crop fields, plantation forests and bush habitats and identified to species or genus level using morphological keys. Fleas, blood samples and gastrointestinal tracts were collected to determine flea infestation, gastrointestinal helminth infections, packed cell volume (PCV) and haemoglobin concentration (Hb). Associations between gastrointestinal helminths, haematological parameters and flea abundance were assessed using generalised linear mixed models. A total of 302 rodents and shrews were captured, with Mastomys natalensis (54.4%, n = 163), Rattus rattus (13.6%, n = 41) and Crocidura spp. (10.3%, n = 31) being the most abundant hosts. Overall gastrointestinal helminth prevalence was 71.2% (95% CI: 65.7–76.2), with Trichuris spp. (33.3%, n = 100), Hymenolepis diminuta (29.1%, n = 88), Angiostrongylus spp. (19.9%, n = 60) and Hymenolepis nana (15.2%, n = 46) being the most prevalent helminths. A total of 271 fleas were collected, predominantly Ctenophthalmus spp. (31.0%, n = 84), Pulex irritans (30.3%, n = 82), Dinopsyllus lypusus (28.8%, n = 78) and Nosopsyllus incisus (4.1%, n = 11). Overall gastrointestinal helminth prevalence was significantly associated with total flea abundance ( p < 0.05), whereas PCV and Hb showed no significant associations ( p > 0.05). These findings suggest that coinfections involving gastrointestinal helminths and fleas are common in small mammals and that helminth infections may influence flea abundance. Understanding these host–parasite interactions may improve our understanding of pathogen transmission dynamics and inform surveillance strategies for zoonotic diseases in Tanzania.

Background: Zoonotic fascioliasis and schistosomiasis, caused by trematode parasites transmitted by freshwater snails, are neglected tropical diseases of both medical and veterinary importance. There are critical knowledge gaps regarding the transmission dynamics of these infections in humans and animals, particularly in endemic African communities. Therefore, the current study aimed to determine the burden of human zoonotic schistosomiasis and fascioliasis among different age groups, focusing on the Lake Victoria zone and the Southern Highlands of Tanzania. Methods: A cross-sectional study was conducted among preschool-aged children, school-aged children, and adults. A total of 1557 stool and urine samples were collected, 400 from preschool children, 804 from school-aged children, and 353 from adults. Stool samples were processed using the Kato–Katz technique and the formol-ether concentration method to detect Schistosoma mansoni and Fasciola spp., respectively. Urine samples were examined for Schistosoma haematobium infection using the urine filtration method. Data were analyzed using Stata version 17. The t-tests or one-way ANOVA were used to assess statistical differences in the mean egg counts of S. mansoni and S. haematobium between exposure groups. Results: The overall prevalence of S. haematobium was 4.9%, S. mansoni was 1.2% with no significant differences across age groups, but with a statistically significant difference between sexes 1.8%. Males had a higher prevalence of both S. haematobium and S. mansoni infections compared to females. The prevalence of Fasciola infection was 0.9%, with the highest prevalence found in adults (≥18 years). Conclusions: Zoonotic schistosomiasis and fascioliasis are prevalent in the study area, affecting individuals across all age groups. This is the first study to report the presence of Fasciola infection in both the Lake Victoria zone and the Southern Highlands of Tanzania. These findings call for the Ministry of Health, through the Tanzania NTD Control Program, to recognize fascioliasis as a high-priority disease and include it in the national master plan.

Background: Zoonotic fascioliasis and schistosomiasis, caused by trematode parasites transmitted by freshwater snails, are neglected tropical diseases with medical and veterinary importance. There are currently knowledge gaps regarding the transmission dynamics of these infections in humans and animals in endemic communities, especially on the African continent. Therefore, the current study aimed to determine the burden of human zoonotic schistosomiasis and fascioliasis among different age groups, focusing on the Lake Victoria and Southern highlands of Tanzania. Methods: A cross-sectional study was conducted among preschool, school-aged children, and adults. A total of 1557 stool and urine samples were collected, 400 from preschool children, 804 from school-aged children, and 353 from adults. Stool samples were processed using the Kato-Katz and the formol-ether concentration methods to examine Schistosoma mansoni (S. mansoni) and Fasciola, respectively. Urine samples were processed using the urine filtration method to examine for Schistosoma haematobium (S. haematobium) infection. While the data analysis was done using Stata V 17, t-test or One-way ANOVA was used to assess the statistical differences in mean egg counts of S. mansoni and S. haematobium exposure groups. Results: The overall prevalence of S. haematobium was 4.9% (95% CI: 0.4–6.1%), S. mansoni was 1.2% (95% CI: 0.7–1.9%) with no age difference but with a significant difference among sex groups 1.8% [ꭓ2(1) =4.47, P =0.034]. Males have a higher prevalence of S. haematobium and S. mansoni than females. The prevalence of Fasciola infection was 0.9% (95% CI: 0.4–1.5%), with the highest prevalence found in adults (≥18 years). Conclusions: Zoonotic schistosomiasis and fascioliasis are prevalent in the study area, affecting all age groups. However, this is the first study of its kind to report the presence of Fasciola infection in Lake Victoria and the Southern highlands of Tanzania. This calls for the Ministry of Health, through the Tanzania NTDs control program, to recognize and include them in the neglected tropical diseases control program as a disease of high priority.

Background: Exploring the nematode diversity in silvery mole rats opens up a fascinating avenue for understanding the intricate relationships between underground-dwelling mammals and their parasites. It is intriguing to consider the potential transmission of parasitic zoonotic between humans, livestock, and silvery mole rats due to the notable interactions of these animals. Purpose: This study aims to acquire crucial information about the nematode fauna in silvery mole rats in the Morogoro region, Tanzania. Method: A survey of nematode parasites in silvery mole rats was conducted in the Morogoro region, from March to June 2023. Collected rats were euthanized using Diethyl Ether, and dissected to remove the gastrointestinal tract (GIT). Adult worms were collected and preserved in 70% ethanol. A flotation method and lactophenol mounting techniques were employed to process gastrointestinal contents and adult roundworms. The prevalence of nematodes was computed, and a chi-square test was applied to assess the relationship, a p-value< 0.05 was considered significant. Results: The examination of the gastrointestinal tract contents revealed two nematode taxa; Physaloptera spp and Strongyloides spp. The overall prevalence of nematode infection was 38.69% (53/137), with Physaloptera species being the most prevalent (37.22%). Adult rats had a lower infection risk than sub-adult rats. Female silvery mole rats were at higher risk of being infected compared to males. Conclusion: The study established two nematodes in silvery mole rats of Morogoro region, Tanzania, which are Physaloptera spp and Strongyloides spp.

Background: Rodents and shrews serve as a reservoirs and final hosts of various parasitic agents. Different factors are known to affect the diversity and distribution of the parasites harbored by them. Little is known on the factors affecting the diversity and distribution of parasites in rodents and shrews found at different elevations in Iringa District. Understanding these factors is crucial to comprehending how parasitic populations among small mammals spread. Purpose: This study aimed to investigate the factors associated with the diversity and distribution of ectoparasites and hemoparasites in rodents and shrews in Iringa. Method: A cross-sectional study was conducted in selected sites between March and June 2023. Rodents and shrews were captured using Sherman and wire traps, euthanized, and then their sex and species were identified. After that, ectoparasites, blood and tissue sample were collected and processed. The diversity and distribution of parasites at different sites were calculated using the Shannon-Wiener Index formula. Results: The overall prevalence of hemoparasites infection was 24.2 % (50/207), dominated by Anaplasma centrale (17.4%:36/207) followed by Plasmodium spp. (8.7%:18/207) and Anaplasma marginale (4.4%:9/207). A total of 713 ectoparasites belonging to five taxa were recovered from small mammals with an overall prevalence of 55.1% (114/207), dominated by mites; Echinolaelaps echidninus 46.4% (96/207), followed by lice; Polyplax spinulosa 16.9% (35/207), tick Hemaphysalis spp. 7.3% (15/207), and two flea taxa; Dinopsylla lypusus 2.9% (6/207) and Xenopsylla cheopis 1% (2/207). Conclusion: The high occurrence of Anaplasma centrale and Echinolaelaps echidninus suggests potential ecological and public health significance.

Trematode infections cause long-term suffering and debilitation, posing a significant threat to global animal health and production and leading to considerable economic losses. Studies on the epidemiology and control of these infections in Tanzania are limited. The few available studies have been conducted in abattoir settings. This study aimed to fill this knowledge gap by determining the prevalence, distribution, and risk factors for trematode infections in domesticated ruminants in two different ecological zones of Tanzania. A cross-sectional study was conducted in the Lake Victoria and the Southern highlands ecological zones of Tanzania. Rectal fecal samples were collected and examined for F. gigantica, Paramphistomidae, and S. bovis infections using the sedimentation technique. A total of 1367 domesticated ruminants were sampled and examined for trematode infections. The overall prevalence of trematode infections was found to be 65.7%. The individual prevalence of F. gigantica, Paramphistomidae, and S. bovis (based on egg morphology only) was 35.1%, 60.2%, and 3.1%, respectively. Adult cattle were more likely to be infected with Paramphistomidae (adjusted odds ratio, (AOR): 1.98; 95% confidence interval, (CI): 1.40–2.78) and S. bovis (AOR: 8.5; 95% CI: 1.12–64.19) than weaners. It was observed that trematode infections in domesticated ruminants are prevalent in the two ecological zones of Tanzania; therefore, effective and community-directed prevention and control strategies are highly needed to address trematode infections of domesticated ruminants in these areas.