Browsing by Author "Mwega, Elisa"

Now showing 1 - 5 of 5

Antibiotic-resistant microbial populations in urban receiving waters and wastewaters from Tanzania
(Elsevier, 2023) Ripanda, Asha; Rwiza, Mwemezi; Nyanza, Elias; Miraji, Hossein; Bih, Numfor; Mzula, Alexanda; Mwega, Elisa; Njau, Karoli; Vuai, Said; Machunda, Revocatus
Antimicrobial resistance against certain medications in the pathogenic microbial community is globally increasing due to the continual discharge and disposal of pharmaceuticals in the environment. The phenomenon resulted in significant antibiotic resistance among several exposed Enterobacteriaceae species, with wastewater treatment plants (WWTPs) and rivers serving as significant reservoirs. Despite antibiotic resistance being a tragedy, particularly in treating diseases by using antibiotics, local and regional studies indicating the severity, resistant species and the molecular level insight into these pathogens are scarce, thus requiring immediate intervention. This study, therefore, investigated wastewater from wastewater treatment ponds and receiving waters for the presence of resistant pathogens through phenotypical and molecular approach screening of their genes. Among the 57 analyzed samples, 18 (67%, n = 27) isolates of Klebsiella spp.., 4 (80%, n = 5) isolates of Proteus spp., 1 (100%, n = 1) of isolated Pseudomonas aeruginosa and 6 (18%, n = 34) of E. coli found were resistant to at least 1 among the tested antibiotics. E. coli had an 83% higher proportion of multi-drug resistance (MDR) than Klebsiella spp.., which had 68.5%, and no MDR was shown by P. aeruginosa isolates. Among the 20 bacterial isolates of antibiotic-resistant genes, showed that E. coli harboured 39%, followed by 22% of Klebsiella spp. Eleven (11) isolates of these 20 (55%) contained sulphonamides resistant genes: Sul 1 (n = 4) and Sul 2 (n = 7). Ten (10) isolates (50%) contained the tetracycline-resistant genes in which 4 isolates showed the Tet A, Tet B – 1 and 5 isolates contained Tet D. β-lactamases (bla CTX-M and bla SHV) were found in 7 isolates (35%). The existence of these antibiotic-resistant species in the urban receiving and wastewater presents a threat of transmission of diseases to humans and animals that are not cured by the existing medications, jeopardizing public health safety.
Associated factors contributing abundance of fleas on rodents in plague endemic area of Karatu district, northern Tanzania.
(IEEE, 2023-07-10) Jakoniko, Joshua; Massawe, Apia; Mwega, Elisa; Kessy, Stella
Fleas are small wingless hematophagous insect that are frequently infesting on rodents and other small mammals while acting as reservoirs and vectors of many rodent borne zoonotic diseases including plague infectious disease which is threat to the public health in many part of the world including Tanzania. 291 rodents from nine species were captured with Sherman traps in farm land, peridomestic areas, bush land and forest buffer zone across wet and dry season in plague and non-plague foci villages. Captured rodents were anaesthetized and 190 fleas comprising four species were collected and morphologically identified with available dichotomous key. Dinopsyllus lypusus were (46.32%), Ctenophthalmus spp (26.84%), Xenopsylla brasiliensis (16.32%) and Xenopsylla cheopis (10.53%). 38.42% of fleas were collected from Mastomy natalensis, 22.63% from Lemniscomys striatus and 18.42% from Rattus rattus. Highest flea infestation prevalence was found on R.rattus and was strongly associated with X.cheopis and X.brasiliensis. Specific flea index of X.cheopis on R.rattus was (01) in plague foci and (<0.5) in non-plague foci villages. Result of GLM final model indicated that flea abundance was significant influenced by rodent species (p < .001), season (p= .031), habitat type (p= .02), rodent weight (p < .001), rodent sex (p < .001) and plague locations (p= .02). There was significance difference in variation of flea abundance between rodent sexes (W = 9158.5, p = .009) and a weak positive correlation between rodent’s weight and abundance of fleas (R= 0.17, p< 0.05). Despite that, specific flea index of X.cheopis on rats in both plague foci and non-plague foci villages were not indicating alarming condition that would require urgent control of fleas, still society should consistently adhere to rodent and fleas control methods in order to limit their interaction to the society especially in farm land and peridomestic areas where human activities are high.
Detection of carrier state and genetic diversity of Theileria parva in ECF-vaccinated and naturally exposed cattle in Tanzania
(Elsevier B.V., 2019-08) Magulu, Emelesiana Cyprian; Kindoro, Fatuma; Mwega, Elisa; Kimera, Sharadhuli; Shirima, Gabriel; Gwakisa, Paul
Infection and Treatment Method (ITM) has been practiced in Tanzania for over 20 years as a prevention measure against East Coast Fever disease. It is known that ITM, like natural ECF infection, leads to a carrier state, whereby vaccinated cattle become asymptomatic carriers of the parasite. It is expected that ECF vaccination using ITM also leads to generation of combinations of vaccine specific Theileria parva and local strains that circulate in the field what contributes to an unknown level of parasite diversity. Moreover, the long term impact of ITM on carrier state and parasite diversity in cattle are largely unknown. To address this question blood was collected from ECF-vaccinated (n = 239) and unvaccinated (n = 97) cattle from Loiborsoit, Emboreet, Esilalei, Manyara ranch and Mswakini villages in the Maasai steppe of northern Tanzania, as well as Mruazi and Leila farms in Tanga in eastern Tanzania. Screening for T. parva using nested PCR revealed an overall prevalence of T. parva to be 34.5%, with a significant higher prevalence among ECF-vaccinated cattle. Using three VNTR markers (ms2, ms5 and MS7) higher parasite genetic diversity in terms of higher number of alleles and expected heterozygosity was shown in vaccinated than unvaccinated cattle. These parameters were highest in cattle from Manyara ranch. Nevertheless, the principle component analysis (PCoA) showed no distinct clustering patterns as most T. parva alleles clustered together throughout the four quadrants implying parasite homogeneity among the sampled populations. However, some of the parasite alleles closely clustered with Muguga vaccine alleles in two of the quadrants, consistent with closer genetic relatedness between the vaccine strains and the T. parva populations from the Maasai steppe. Likewise analysis of molecular variance (AMOVA) revealed most of the genetic variation (93%) being contained within populations with only 7% being among populations. This study therefore confirms the role of ECF vaccination in enhancing carrier state and T. parva diversity in vaccinated cattle populations. Higher T. parva diversity may play an important role in carrier cattle by way of restricting breakthrough infections from field parasite strains.
Flea Burden on Rodents and Its Associated Determinants in Plague-Endemic Localities of Karatu District, Tanzania: A Cross-Sectional Study
(Wiley, 2024-06-22) Jakoniko, Joshua; Massawe, Apia; Mwega, Elisa; Kessy, Stella
Background Fleas infest rodents and other small mammals, serving as vectors for zoonotic diseases such as plague. This study investigates the flea burden on rodents and its associated determinants within the plague-endemic localities of Karatu district, Tanzania. Methods A repeated cross-sectional design was employed to capture rodents with Sherman traps in farmland, peridomestic area, bush land, and forest buffer zones across the wet and dry seasons of 2022 in plague and nonplague foci villages. Captured rodents were anaesthetized and thoroughly brushed to collect fleas, which were then identified using a dichotomous key. Results A total of 291 rodents (9 species) were captured, from which 190 fleas (4 species) were collected. The collected fleas were Dinopsyllus lypusus (46.32%), Ctenophthalmus sp (26.84%), Xenopsylla brasiliensis (16.32%), and Xenopsylla cheopis (10.53%). Approximately 38.42% of fleas were found on Mastomys natalensis, 22.63% on Lemniscomys striatus, and 18.42% on Rattus rattus. High flea abundance was recorded in farmland and peridomestic areas. The specific flea index (SFI) of X. cheopis on R. rattus was 1.0 in plague foci and <0.5 in nonplague foci. A generalized linear model revealed significant influences of rodent species, season, habitats, rodent weight, sex, and plague locations on flea abundance. Significant variation was observed between rodent sexes (p = 0.009), and a weak positive correlation existed between rodent weight and flea abundance (R = 0.17, p < 0.05). Conclusion Villages in plague foci exhibited higher abundances of fleas in comparison to nonplague foci villages. The SFI results for X. cheopis on rats in both types of villages did not surpass critical thresholds. Factors such as dry season, farmlands, and rodent characteristics influenced flea abundance on rodents in the study area.
Incremental effect of natural tick challenge on the infection and treatment method-induced immunity against T. parva in cattle under agro-pastoral systems in Northern Tanzania
(Elsevier, 2015-07-01) Kazungu, Yvette; Mwega, Elisa; Neselle, Moses; Sallu, Raphael; Kimera, Sharadhuli; Gwakisa, Paul
This study was conducted to assess the incremental effect of natural tick challenge on the infection and treatment method-induced immunity against T. parva under agro-pastoral systems in Simanjiro district, Northern Tanzania. T. parva specific antibody percent positivity and prevalence of T. parva parasites were studied in relation to duration post vaccination and proximity to Tarangire National park. A total of 381 cattle were included in this study, of which 127 were unvaccinated and 254 had been vaccinated at different time points between 2008 and 2014. Antibody percent positivity (PP) determined by the PIM-based T. parva ELISA and the prevalence of T. parva parasites detected by a nested PCR based on the p104 gene were used to compare vaccinated and unvaccinated cattle. Results showed that seroprevalence was significantly higher in vaccinated than unvaccinated cattle (OR 10.89, p = 0.0341). Only 1.6% (6/381) of all cattle were seronegative and 5/6 of these were unvaccinated. Prevalence of T. parva parasites was significantly higher in vaccinated (50.39%) than unvaccinated (19.69%) cattle (OR 2.03, p = 0.0144). While there was a positive association between PP and duration post vaccination but the latter was inversely associated with T. parva parasite prevalence. This study also showed that cattle which were closer to the park had higher antibody PP and T. parva prevalence. It is concluded that duration post vaccination as well as proximity from the wildlife in Tarangire National park together may exert an incremental effect on the outcome of ECF vaccination by influencing stronger antibody immunity of cattle and ability to withhold high T. parva infection pressure under constant field tick challenge. Further, the high seroprevalence in vaccinated and unvaccinated cattle suggests a likely state of endemic stability to T. parva in the study area.