A Preliminary Investigation on a Commercial Ovine Pasteurellosis Vaccine Using Clinical and Pathological Endpoints.

Introduction: In this study we aimed to provide preliminary evidence on the safety and efficacy of the currently used ovine pasteurellosis vaccine in Ethiopia using clinical and pathological endpoints. Methods: Twenty, conventionally reared, apparently healthy, seronegative male lambs, were randomly classified into two groups of 10 animals as "vaccinated-challenged" and "unvaccinated-challenged controls". The first group received 1 mL of the licensed Pasteurella multocida biotype A based vaccine subcutaneously while the second group received phosphate-buffered saline as a placebo. Following vaccination, lambs were monitored for one month for potential vaccine adverse reactions. Five weeks postvaccination, all lambs were immunosuppressed using dexamethasone, and intratracheally challenged with 5.2×109 CFU/mL live Mannheimia haemolytica A1 (clinical isolates). Then, all lambs were followed up for eight days for clinical examination and necropsied on the ninth day postchallenge for pathological investigation. Results: There were no safety issues recorded during the study. In terms of clinical signs, lambs developed fever, depression, mucoid bilateral oculonasal discharge, coughing and sneezing regardless of their vaccination status. Fisher's exact test between vaccination status and each clinical sign showed a statistically insignificant association (p>0.05). The main pathological findings in both groups were pulmonary congestion, atelectasis, emphysema, and suppurative bronchopneumonia. Consolidation lung lesion score of +1 (5/10 of vaccinated, 6/10 of unvaccinated) and +2 (3/10 of vaccinated, 4/10 of unvaccinated) were recorded in a statistically indifferent manner among both vaccinated and nonvaccinated groups (p>0.05). Discussion and Conclusion: Collectively, the results suggested that the vaccine posed no safety concern and presumably lacks protective efficacy against local isolates. However, the study did not analyze antibody titer and their functionality using serum bactericidal assays. Further confirmatory studies could provide more evidence on the vaccine efficacy. Safety should further be assessed in a field setting involving a large number of animals to enable detection of rare vaccine adverse events.

Toxoplasma gondii infection in backyard chickens (Gallus domesticus): Seroprevalence and associated risk factors in Northwest Ethiopia.

Limited data is accessible about the seroprevalence of Toxoplasma gondii infection in backyard (free-range) chickens in Ethiopia. This cross-sectional study was carried out from November 2018 to April 2019 to estimate the seroprevalence and assess associated risk factors of T. gondii infection in backyard chickens in Northwest Ethiopia. Serum samples were collected from 384 backyard chickens. Toxoplasma gondii antibodies were assayed using Toxo-Latex slide agglutination test. Seropositivity for T. gondii antibodies was confirmed in 72.4% of 384 birds. Altitude, presence of cat and dog around the house, age, breed and water source were considered as potential risk factors (p < .05) associated with Toxoplasma seropositivity in this study. But, sex was not identified as a predictor for Toxoplasma infection even though higher seroprevalence was observed in females (73.7%) than males (69.3%). In conclusion, this study indicates a high prevalence of T. gondii infection in backyard chickens in Northwest Ethiopia. Therefore, further works on epidemiology, bioassay, isolation and genetic characterization of the pathogen are imperative. It also warrants an action to prevent and control T. gondii infection in backyard chickens that could serve as an important intermediate host and pose a potential threat for consumers.

Smear-Positive Tuberculosis Prevalence and Associated Factors among Pregnant Women Attending Antinatal Care in North Gondar Zone Hospitals, Ethiopia.

Tuberculosis is an ancient infectious disease that remains a threat to public health around the world. It is a contagious airborne disease caused by Mycobacterium tuberculosis complex. In high tuberculosis burden countries, the prevalence of tuberculosis was 10-fold higher in the HIV-infected mothers than that in those not infected with HIV. However, little is known about the burden of tuberculosis (TB) and associated factors in women of reproductive age in most resource poor countries. Therefore, this study aims to investigate prevalence of smear-positive TB and factors associated in pregnant women attending antenatal care in North West, Ethiopia. An institution-based cross-sectional study was conducted in three governmental hospitals of the North Gondar Zone, and a total of 1272 pregnant women attending antenatal care were included. Data were collected by trained personnel's using a pretested and structured symptom screening questionnaire; then, spot-morning-spot sputum samples were collected from those pregnant women who had two or more weeks of cough, and sputum smear was done by using a light-emitted diode fluorescent microscope. 99% of the pregnant women visited the hospitals for antenatal care. The prevalence of smear-positive tuberculosis was 864/100,000 population, and HIV positivity (AOR = 7.24; 95% CI: (2.01-26.03)), urban residence (AOR = 2.28; 95% CI: (1.419-3.158)), and family history of TB (AOR = 2.12; 95% CI: (1.371-3.451)) were significantly associated with smear-positive tuberculosis. In this study, the prevalence of smear-positive tuberculosis was found to be higher than that in other community-based studies in the country. Therefore, health education, targeted screening of pregnant women for TB, and collaboration of TB-HIV clinic with antenatal care clinic should be implemented in the area. Further research should also be conducted for better understanding of the magnitude of tuberculosis in females of reproductive age.