Preliminary survey of domestic animal visceral leishmaniasis and risk factors in north-west Ethiopia.

OBJECTIVE: After the epidemics of L. donovani complex in 2004/05 in human patients, to investigate the presence of antibodies against L. donovani in domestic animals in north-west Ethiopia. METHODS: Two hundred and three domestic animals were screened. Serum and biopsy samples were collected. A modified direct agglutination test (DAT) for canine reservoirs was used to screen serum samples at ≥ 1:320 cut-off titre. Giemsa stain and culture on Novy macNeal Nicolae (NNN) media were used for biopsy samples. Pre-tested questionnaires were used to elicit information on potential risk factors. RESULTS: Antibody against L. donovani in domestic animals was detected in 30.5% of animals. The highest seropositivity rates were 41.9% in cattle, 40% in dogs, 33.3% in donkeys, 10% in goats and 4.8% in sheep. No Leishmania parasite was isolated from spleen, liver, skin snip and exudates, bone marrow or lymph node of dogs. Dogs owned by households with history of kala-azar treatment and humans sharing the house with cattle were more affected by visceral leishmaniasis (P < 0.05). CONCLUSION: This study showed a high serological prevalence of leishmaniasis in domestic animals. Their role in the epidemiology of visceral leishmaniasis remains unclear.

Seroprevalence and associated risk factors of equine herpesvirus type-1/-4 in selected districts of Northwest Amhara, Ethiopia.

This study aimed to estimate the prevalence, determine the distribution, and identify the epidemiological risk factors of EHV-1/-4 infections in selected districts of Northwest Amhara Region. 460 serum samples were collected from equines using multistage cluster sampling technique, and a competitive Enzyme-linked immunosorbent assay (cELISA) was performed. Various risk factors for the occurrence of EHV-1/-4 were considered. Statistical analysis was performed using R version 4.3.1. 65.9% (303) equids were tested positive for antibodies against EHV-1/-4. Based on district, the highest prevalence was recorded in Wogera (86.1%), while the lowest was in Debark (47.4%). There was a significant difference (p <0.05; 95% CI: 1.1067993-3.682843) in the prevalence of EHV-1/-4 among species and donkeys are 2.019 times more likely to get an EHV infection than horses. The prevalence of EHV-1/-4 was highest in equids with the age of 3-8 years and lowest in < 3 years, and the difference was statistically significant (p <0.05; 95% CI: 1.9812042-6.771820). Statistically significant variation (p <0.05; 95% CI: 1.1173822-2.684013) was also observed between sex of equids in which females had 1.73 times higher chance to get EHV infection than males. Higher prevalence was found in lactating equids (81.6%), followed by pregnant equids (74.6%), and dry equids (66.4%). Generally, this study indicated a high and wide distribution of EHV-1/-4 infection in the study area, which needs due attention. Devising strategies to prevent and minimize the spread and occurrence of the infection is crucial.

Risk factors associated with contagious caprine pleuropneumonia in goats of Amhara region, Ethiopia.

Contagious caprine pleuropneumonia (CCPP) is a serious contagious disease of goats, sheep and wild ruminants caused by Mycoplasma capricolum subspecies capripneumoniae. The disease is known for its high mortality, morbidity and economic losses. A cross-sectional study using multistage cluster sampling technique was conducted in Amhara region from January 2019 to July 2019 to estimate seroprevalence and identify risk factors of CCPP occurrence in the region. A total of 2080 goats from 61 villages and 12 districts of the region were tested for CCPP serostatus using Competitive Enzyme-Linked Immunosorbent Assay (C-ELISA). A multilevel mixed-effect logistic regression model was used to identify risk factors of CCPP seropositivity at animal and flock-level. The serum sample results revealed an overall animal level seroprevalence of 5.1% (95% CI: 3.8-6.6) and flock-level prevalence of 26.0% (95% CI: 19.7-33.4). At individual animal level, presence of other health problems (OR = 45.9 (95% CI: 25.3-83.4)), age (adult age (OR = 6.2 (95% CI:3.4-11.4)) and old age (OR = 13.1 (95% CI: 6.2-27.8))), and breed type (Afar (OR= 32.3 (95% CI: 2.9-366.1)), Central highland (OR=13.7 (95% CI: 1.3-140.6)), and western highland (OR=16.2 (95% CI: 1.4-185.7))) were identified as risk factors for CCPP seropositivity. In contrast, contact with other flocks (OR = 59.9 (95% CI: 6.1-585.6)), presence of trade route (OR = 3.1 (95% CI: 1.0-9.1)) and presence of sheep (OR = 2.6 (95% CI: 1.2-5.7)) were flock-level risk factors for CCPP seropositivity. Generally, CCPP appears to be common among goats of Amhara region. Goat flocks dominated with older age animals; breeds of Afar, central highland, and western highland; raise with sheep; have contact with other flocks; and kept along trade routes are more at risk for CCPP. Hence, awareness creation to the producers, movement control, and regular prophylactic vaccination should be considered to control CCPP in Amhara region.

Toxoplasma gondii infection in slaughtered domestic ruminants in Northwest Ethiopia: occurrence, bioassay and virulence assessment.

This study investigated the occurrence, isolation and virulence of Toxoplasma gondii in slaughtered domestic ruminants in Gondar, Northwest Ethiopia. Three hundred thirty-five blood samples (135 sheep, 50 goats, and 150 cattle) were purposefully collected from abattoirs and slaughterhouses. T. gondii antibodies were assessed using a commercial Toxo-Latex agglutination test. Tissue digestion with the pepsin enzyme was also performed on 39 heart muscles of seropositive animals, and viable T. gondii was isolated in white albino mice. As a result, the occurrence of T. gondii infection was 55.8%. T. gondii antibodies were found in 59.3% of cattle, 58% of goats, and 51.1% of sheep. The prevalence of T. gondii antibodies in sheep was significantly higher in females (χ2 = 4.55, p = 0.033) and adults (χ2 = 7.57, p = 0.006). Similarly, in cattle, the presence of T. gondii antibodies was associated with old groups (χ2 = 7.81, p = 0.005) and cross-breeds (χ2 = 6.30, p = 0.012). The overall viable T. gondii isolates in bioassayed mice were 38.5%, and the parasites were isolated from sheep (8/16), cattle (3/14) and goats (4/9) samples, with the majority of these isolates (87.2%) being avirulent. In conclusion, the presence of T. gondii antibodies and a high proportion of viable T. gondii in this study may indicate the parasite's prevalence and zoonotic importance in the study area. To plan control strategies, more research on the genotype and transmission dynamics of this parasite is required. Public education about T. gondii transmission routes and control methods is critical for preventing T. gondii transmission.

Isolation and Molecular Detection of Pasteurellosis from Pneumonic Sheep in Selected Areas of Amhara Region, Ethiopia: An Implication for Designing Effective Ovine Pasteurellosis Vaccine.

Introduction: Pneumonic pasteurellosis mainly caused by bacterial species of Mannheimia, Pasteurella, and Bibersteinia causes a significant financial loss to the sheep production sector through reduced productivity and high mortality. There is a dearth of information on the major agents involved in the disease in the Amhara region, Ethiopia. Therefore, the aim of this study was to isolate and molecularly confirm Mannheimia, Pasteurella, and Bibersteinia from nasal swabs of sheep suspected of pneumonic pasteurellosis in selected areas of the Amhara region. Methods: Isolation and phenotypic characterization were performed using microbiological and biochemical testing according to standard methods. Molecular confirmation of isolates was done through amplification of virulence associated genes, PHSAA and Rpt2, of Mannheimia hemolyticausing multiplex PCR. Results: Accordingly, 46 out of 141 (32.62%) samples were presumably identified as M. hemolytica with no Pasteurella multocida and Bibersteinia trehalosi. Seven (n=7) out of the 46 isolates tested positive for either of the two virulence genes. Discussion and conclusion: The finding of this study is indicative that M. hemolytica is the main bacteria linked with pneumonic pasteurellosis in the study area which suggests the need to develop a polyvalent vaccine including strains of M. hemolytica or its antigenic determinants. However, the role of other bacterial, viral, and parasitic agents in the cases investigated should also be considered.

Foot and Mouth Disease Vaccine Development and Challenges in Inducing Long-Lasting Immunity: Trends and Current Perspectives.

Foot and mouth disease (FMD) is an extremely contagious viral disease of livestock caused by foot and mouse disease virus genus: Aphthovirus, which causes a serious economic impact on both individual farmers and the national economy. Many attempts to advance a vaccine for FMD have failed to induce sterile immunity. The classical methods of vaccine production were due to selective accumulation of mutations around antigenic and binding sites. Reversion of the agent by positive selection and quasi-species swarm, use of this method is inapplicable for use in non-endemic areas. Chemical attenuation using binary ethyleneimine (BEI) protected the capsid integrity and produced a pronounced immunity against the challenge strain. Viral antigens which have been chemically synthesized or expressed in viruses, plasmid, or plants were tried in the vaccination of animals. DNA vaccines expressing either structural or nonstructural protein antigens have been tried to immunize animals. Using interleukins as a genetic adjuvant for DNA vaccines have a promising effect. While the challenges of inducing sterile immunity lies on non-structural (NS) proteins of FMDV which are responsible for apoptosis of dendritic cells and have negative effects on lympho-proliferative responses which lead to transient immunosuppression. Furthermore, destruction of host protein trafficking by nonstructural proteins suppressed CD8 + T-cell proliferation. In this review, it tried to address multiple approaches for vaccine development trials and bottle necks of producing sterile immunity.

Assessment of the Impact of Sheep and Goat Pox Lesions on Skin Quality in Selected Ware Houses of Central Ethiopia.

BACKGROUND: The study was performed from January 2016 to May 2017 with the aim of identifying the impact of sheep and goat pox in skin quality in selected localities of central Ethiopia. MATERIALS AND METHODS: A total of 1360 fresh, salted and dried skins were examined and graded. Pox lesion positive skins were examined by PCR to identify the agent. RESULTS: The prevalence of sheep and goat in the study areas was 4.022%. From a total of 86 rejected skins, a large number of skins were in the rejected category (2.78%). There were highly statistically significant associations (p < 0.05) between sheep and goat pox and species and study areas. However, there were no statically significant associations (p > 0.05) between skin size and sheep and pox. Molecular diagnosis of the case revealed that goat pox virus was responsible for the lesion. CONCLUSION: Goat pox virus is the main cause of skin rejection and the factor that causes downgrading of skin.

Evaluation of the Antimicrobial Activity of Leaf Extracts of Acokanthera schimperi against Various Disease-Causing Bacteria.

BACKGROUND: In traditional medicine of Ethiopia, Acokanthera schimperi is the one used to treat different infectious diseases. Hence, this study was conducted with the main aim of determining active compounds in the leaves of A. schimperi. METHODS: The antimicrobial activities of using disk diffusion, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) and acute oral toxicity of the fraction. RESULTS: The average bacterial zone of inhibition of the dichloromethane (DCM), chloroform (TCM), petroleum ether (PE) and ethyl acetate (EA) fractions ranged from 7.67 mm to 18.12 mm. The average values of MIC of the DCM, TCM, PE and EA fractions ranged from 4.17 mg/mL to 33.34 mg/mL. The most susceptible bacterium at 200 mg/mL was S. typhi, (18.12mm), while the less susceptible bacterium was C. freundii (14.33mm). CONCLUSION: The solvent fractions demonstrated significant antibacterial activities with varying spectrum and safe up to 2000mg/kg.

Antioxidant and Antimicrobial Activity of Solvent Fractions of Calpurnia aurea (Ait.) Benth. (Fabaceae).

BACKGROUND: Calpurnia aurea (Ait.) Benth. leaves are used to treat different diseases like ectoparasite infestation, diarrhea, sores, anthrax, fevers, pain, and snake venom. The leaves of Calpurnia aurea were first extracted by methanol and further fractionated with the help of n-hexane, dichloromethane and ethyl acetate with increasing polarity. METHODS: The antibacterial activities of the fractions were evaluated against disease causing bacteria using agar well diffusion. The minimum inhibitory concentrations (MIC) of the fractions were determined by the micro-broth dilution method using tetrazolium salt colorimetric assay. The antioxidant activities of the solvent fractions were determined by phospho-molbedum reduction assay, reducing power assay and hydroxyl radical scavenging activity. RESULTS: The average MIC value of C. aurea fractions ranged from 1.95mg/mL to 31.25mg/mL, 7.81mg/mL to 31.25mg/mL and 13.02mg/mL to 62.5mg/mL, for ethyl acetate, dichloromethane and n-hexane fractions, respectively. The leaf extracts have a higher antioxidant effect, as shown in the phospho-molbedum reduction assay, reducing power and hydroxyl radical scavenging assay. CONCLUSION: The ethyl acetate and dichloromethane fractions revealed significant antibacterial effects against the growth of pathogenic bacteria. However, the n-hexane fraction showed the least antibacterial effect against all of the test bacteria. Furthermore, the n-hexane fractions of C. aurea showed higher antioxidant activity.

Evaluation of Anthelminthic Activity of Tropical Taniferous Plant Extracts Against Haemonchus contortus.

INTRODUCTION: The present trial aimed to investigate invitro anthelminthic activities of selected tropical tanniferous plant extract on egg hatchability and larval development inhibition of Haemonchus contortus in sheep. In view of that, three tropical tanniferous plants Rhus glutinosa, Syzygium guineensa and Albizia gumifera, were selected based on their relative high content of condensed tannins. METHODS: In this study, eggs were collected from artificially infected with H. contortus. Then the egg was directly subjected to invitro assay with these condensed tannin-enriched extracts using egg hatchability assay and inhibition of larval development assay. RESULTS: The result showed that extracts from all three tropical tanniferous plants demonstrated statistically significant (P < 0.05) dosedependent inhibition of both egg hatchability and larval development. According to IC50 and IC90 values, the condensed tannin-enriched extracts inhibiting egg hatching and larval development most potently were Rhus glutinosa followed in descending order of activity by Syzygium guineensa and Albizia gumifera. DISCUSSION: The result of this study showed that these condensed tanninenriched extracts were effective in inhibiting egg hatchability as well as larval development. Therefore, condensed tannin might be recommended as one of the options for the control of H. contortus in sheep.