Veterinary Parasitology

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Browsing Veterinary Parasitology by Author "Dr. Ahmed Yasin"

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    EXPERIMENTAL STUDIES ON CLINICO- HEMATOLOGY OF TRYPANOSOMA EQUIPERDUM INFECTED HORSES AND VENEREAL TRANSMISSION IN MICE
    (2017-06) Merga, Daba; Dr. Hagos Ashenafi, Merga Bekana (Prof); Dr. Ahmed Yasin
    Dourine is an endemic venereal transmitted trypanosomosis causing a major health problem threatening the life and productivity of the equine population in Ethiopia. The present experimental study was conducted from November 2016 to June 2017 in Bishoftu, central Oromia, Ethiopia. The objective of the study was to evaluating clinico-hematological profile of horses experimentally infected with Trypanosoma equiperdum, assess the effect of cymelarsan treatment on hematological values of horses infected with T. equiperdum and determine the possibility of venereal transmission of T. equiperdum in mice. The study design was conducted on (n=4) mares and (n=4) stallions. Mares were challenged by insemination of semen originated from non-infected stallion after mixed with T. equiperdum at a dose of 100,000 parasite/ml by artificial insemination whereas stallion group were infected with 2ml of blood that drawn from infected mare at dose of 1x106 parasites /ml via intravenous route. Data on parasitaemia, rectal temperature, serology (CATT/T. evansi test) and hematological were determined before and after infection. Furthermore infected horses were divided into two groups designated as treated and non-treated groups. At weeks 6 of post infection treatment group was injected with cymelarsan® at dose of 0.25mg/kg body weight. Changes in clinical sign, parasitemia and hematological values were monitored. Thirty (n=30) female mice and male (n=12) were involved in experiment to check coital transmission. One infected mouse was co-housed with two healthy female mice at low level of parasitemia (1x101-1x103) in six replications and other one infected male mouse co-housed with two healthy female mice at high level of parasitemia (1x104-1x106) in six replications. Other two infected female co-housed with four healthy female as control. Thereafter the appearance of Parasitemia was monitored daily from female mice. The study revealed that, Dodola strain caused a severe change in blood parameter and a clinical sign in both stallion and mare, infection was predominantly characterized by involvement of genital, nervous and corneal signs. There was significant decrease in mean PCV, Hg, RBC, eosinophil, basophil and monocyte count while mean total WBC and neutrophil count had no significant difference (p>0.05) in animals post-infection when compared to pre-infection values. Lymphocyte and MCHC were significantly (p<0.05) higher at post infection as compared to pre-infection. Cymelarsan treatment at dose of 0.25 mg/kg body weight failed to clear the parasite and improve in clinico-hematological values, rather being relapsed after 21days. Treated group had no significant improvement in RBC, Hgb, and differential leukocyte count whereas PCV and WBC which were significantly (p < 0.05) improved as compared to non-treated group. In healthy female mice co-housed with infected male mice using wet smear no trypanosomes were detected in all female mice and their offspring in wet smear throughout study period. In conclusion the current study revealed that dourine resulted in hematological changes that lead to normocytic hypochromic anemia, thus further elucidative investigation recommended on pathogenesis of the disease. In addition, venereal transmission of T. equiperdum in mice was unsuccessful; hence further molecular based test is essential to ascertain this result.
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    STUDY ON IN VITRO LOUSCIDAL AND ACARICIDAL PROPERTIES OF CALPURNIA AUREA, OTOSTEGIA INTEGRIFOLIA, NICOTIANA TABACCUM AND JATROPHA CURCAS AGAINST BOVICOLA OVIS AND AMBLYOMMA VARIEGATUM
    (2015-06) Sisay, Alemu; Dr. Yacob Hailu, Dr. Getachew Terefe; Dr. Mirutse Giday; Dr. Ahmed Yasin
    The present study was designed to evaluate the preliminary phytochemicals present in methanolic leaf extracts of Calpurnia aurea, Otostegia integrifolia, Nicotiana tabaccum and petroleum ether seed oil extract of Jatropha curcas and to assess their in vitro louscidal and accaricidal efficacy. Accordingly, each plant was subjected to qualitative phytochemical screening for the presence or absence of secondary metabolites such as alkaloids, steroidal compounds, phenolic compounds, flavonoids, saponins, tannins, phlobatannins, triterpens and glycosides using standard procedures. The four selected medicinal plants and a commercially used acaricide (0.1% diazinon) were examined for their louscidal and acaricidal activity against B. ovis and A. variegatum at different time intervals using the in vitro adult immersion test at concentrations of 200, 100, 50, 25, 12.5 and 6.25 mg/ml. The findings revealed that extracts of C. aurea leaf and J. curcas seed oil caused high mortalities of B. ovis at all concentrations with no significant difference from the activity of 0.1% diazinon ( > 0.05) within 24 hours of exposure. Moreover, at 200 mg/ml concentration, crude extracts of N. tabaccum and O. integrifolia produced 93% and 63% mortality respectively against B. ovis within 24 hours of exposure. The extracts of all four plants were also examined for their acaricidal activity against A. vareigatum. Although, the effects of the extracts on this tick species was much lower than what was observed on lice, the extracts of C. aurea leaf and J. curcas seed oil have shown 56% and 39% mortality at 200 and 100 mg/ml concentrations, respectively within 24 hrs exposure of the parasite and was comparable to the acaricidal activity of 0.1% diazinon ( > 0.05). A similar situation was caused by crude extracts of N. tabaccum which was 44% and 39% mortality at concentrations of 200 and 100 mg/ml within 24 hrs of exposure, respectively. However, O. integrifolia showed significantly lower acaricidal activity ( < 0.05) when compared to the reference drug (0.1% diazinon). The current study revealed that crude extracts of C. aurea leaf and J. curcas seed oil have strong louscidal activity. Moreover, crude extracts C. aurea and J. curcas showed high mortality at lower concentrations and can be used as a potential alternative to synthetic acaricides to control B. ovis infestations. Though, they are not effective at lower concentrations, crude extracts of C. aurea, N. tabaccum and J. curcas seed oil had better acaricidal effects on cattle ticks at higher concentrations. This is a promising finding to have an alternative means of treatment to substitute the use of synthetic drugs which have a widespread drug resistance especially in developing countries including Ethiopia. xiv Therefore, further investigation should be made on their safety and in vivo efficacy as well as cost effectiveness of the products that exhibited strong louscidal and acaricidal activity with a view of substituting the conventional synthetic acaricides.