Prevalence of cattle ixodid ticks and acaricides efficacy evaluation in Amibara district of Afar Region, Ethiopia.

A cross sectional and randomized controlled trial study was conducted starting from July 2021 to July 2022 to determine the prevalence of ixodid ticks, and evaluate the efficacy of commonly used acaricides (amitraz 12.5% and diazinon 60%) in vitro and in vivo on cattle ticks in Amibara district. A total of 372 cattle were visited randomly from six kebeles of the district which were selected based on their livestock population. A total of 4330 adult ticks were collected and identified to the species level with stereomicroscope. For the invitro acaricide efficacy test, 90 engorged female ticks were collected from infested herds and grouped into three, each group having ten engorged ticks; two groups for the two test acaricides and the third groups were control to evaluate these acaricides in the laboratory. All the groups were replicated three times and incubated for seven days with similar temperature and humidity. Thirty-six infested cattle were selected and again grouped into three randomly, 12 each for the invivo test. The first groups of animals were sprayed with amitraz, the second with diazinon and the third groups were left untreated. Ticks were counted and recorded before, day 3, day 7, day 14 and day 21 of spraying. A total of 360 (96.7%) of the visited cattle were infested with ticks. Amblyomma. Rhipicephallus, Hyalomma and Bophillus were the genera of ticks identified with a prevalence of 44.9%, 41.4%, 7.5% and 6.2% respectively. A total of 15 species of ixodid ticks were identified from which Rhipicephallus pulchellus (39.86%) was dominant followed by Amblyomma lepidum (26.65%) and Amblyomma gemma (14.36%). Diazinon 60% EC and amitraz 12.5% were significantly inhibited the egg laying ability of engorged ticks' in vitro with percent inhibition of 100% and 99.1% respectively. On live animal, both acaricides showed statistically significant difference from the control group (p- value <0.05) with maximum 97.37% (amitraz) and 93.33% (diazinon) at day 7 and minimum 73.3% (amitraz) and 73.7% (diazinon) efficacy. However, there was no statistically significant difference on egg laying inhibition and tick count reduction between the two acaricides (p-value >0.05). Therefore, awareness should be created about the high prevalence as well as the application, dosage and dilution of the acaricides to pastoralists, community animal health workers and para veterinarians in the study area. Cattle owners, veterinarians and concerned government officials should address infested herds with manufacturer recommended dosage of these acaricides to control the tick infestation.

Isolation, identification and antimicrobial profile of methicillin-resistant Staphylococcus aureus from bovine mastitis in and around Adama, Central Ethiopia.

BACKGROUND: Among bacterial pathogens, Staphylococcus aureus which lives in the mammary gland is the leading cause of bovine mastitis worldwide, which causes enormous economic losses to the dairy industry. OBJECTIVES AND METHODS: The study was carried out cross-sectionally to determine the occurrence of methicillin-resistant S. aureus (MRSA) and the risk factors for mastitis infection in dairy cows in and around Adama from October 2014 to June 2015. This particular study included 384 animals. Milk samples were collected and screened with California mastitis test. Then bacteria were cultured and identified using biochemical tests and disc diffusion test was used to determine the antimicrobial sensitivity for MRSA. RESULTS: The prevalence of mastitis was 121 (31.5%). Among them, 37 cases (30.6%) were clinical mastitis and 84 cases (69.4%) were subclinical mastitis. Among these positive cases, 37 cases (30.6%) of S. aureus were isolated. The prevalence of mastitis was significantly related to the breed, age, floor type and sanitation status of the milking (p <0.05). The Kirby-Bauer disc diffusion method was performed on Mueller Hinton agar medium according to NCCLS guidelines to test antibiotic sensitivity. The 32.4% of S. aureus isolates were resistant to oxacillin. Isolates of MRSA are more resistant to amoxicillin (75%), oxytetracycline (66.7%) and sulfa (50%). However, they were sensitive to kanamycin (75%), streptomycin (58.3%) and nalidixic acid (50%). Insufficient dosage, short treatment time and chronic infection in dairy cows in the herd are the main reasons for the large number of resistant strains. CONCLUSION AND RECOMMENDATION: Generally, mastitis was prevalent in the area, and it was resistant to commonly used antibiotics. Therefore, hygienic, prevention and alternative treatment methods should be implemented.

Efficacy of diminazene diaceturate and isometamidium chloride hydrochloride for the treatment of Trypanosoma evansi in mice model.

Diminazene diaceturate (DIM) and isometamidium chloride hydrochloride (ISMM) have been widely used for the treatment of animal trypanosomosis. We evaluated the efficacy of standard doses of DIM and ISMM followed by their double doses for the treatment of Trypanosoma evansi in experimentally infected mice. A T. evansi strain obtained from a naturally infected camel in Afar was used. 25 swiss white mice randomly divided in to five groups were inoculated with 0.2 mL of blood containing 103 trypanosomes. At the peak of parasitemia (≈ 2 weeks post infection), groups A and B were treated with the standard dose (3.5 mg/kg body weight [BWT]) of DIM; groups C and D were treated with the standard dose (0.5 mg/kg BWT) of ISMM; and group E served as infected control. In the DIM standard dose groups, relapses and peak parasitemia were observed 20- and 25-days post treatment respectively. Similarly, relapses and peak parasitemia were observed 21- and 27-days post treatment in the ISMM standard dose groups. All mice in the control group died within two weeks post infection. Following relapses, mice were treated with the double doses of DIM (7 mg/kg BWT) or ISMM (1 mg/kg BWT). Parasitemia was not detected for 3 months following the double dose treatments. Following dexamethasone administration for 7 days, all but one mouse in the DIM group remained negative for another month. In general, although the T. evansi strain was resistant to the standard doses of DIM and ISMM their double doses completely cleared the infection.