Resistance to trypanocidal drugs has been detected in various African countries and is a serious impediment to the control of livestock trypanosomosis. To determine whether drug resistant trypanosome strains are present in the Zambézia Province of Mozambique a study was initiated. To assess the effect of the farming system and the drug-use regimen on the development of drug resistance, trypanosome isolates were collected from cattle from subsistence and commercial livestock production systems. The susceptibility of seven isolates against isometamidium chloride, diminazene aceturate and homidium chloride was tested in mice using a multiple-dose test. In four of the seven isolates high levels of drug resistance to diminazene aceturate and isometamidium chloride were detected. In most cases the observed levels of drug resistance correlated with the drug-use practices in the particular livestock production system.

A survey to determine the prevalence of bovine tuberculosis caused by Mycobacterium bovis and certain other infectious diseases was conducted on 42 free-ranging African buffaloes, (Syncerus caffer) from May to June 1997 in the Queen Elizabeth National Park, Uganda. Using the gamma interferon test, exposure to M. bovis was detected in 21.6 % of the buffaloes. One dead buffalo and an emaciated warthog (Phacochoerus aethiopicus) that was euthanased, were necropsied; both had miliary granulomas from which M. bovis was isolated. None of the buffaloes sampled in Sector A of the park, which has no cattle interface, tested positive for bovine tuberculosis (BTB) exposure. The prevalence and distribution of BTB does not appear to have changed significantly since the 1960s, but this may be due to fluxes in the buffalo population. Serological testing for foot-and-mouth disease (FMD) demonstrated positive exposure of 57.1% of the buffaloes sampled, with types A, O and SAT 1-3, which is the first known report of FMD antibodies to A and O types in free ranging African buffaloes. Foot-and-mouth disease virus types SAT 1 and SAT 3 were isolated from buffalo probang samples. Two percent of the buffaloes had been exposed to brucellosis. None of the buffaloes tested had antibodies to rinderpest, leptospirosis or Q fever.

A conclusive study was conducted for preparation and evaluation of combined inactivated entero-4 vaccine containing bovine rotavirus (BRV), bovine coronavirus (BCV), E. coli K99 and toxoid of C. perfringens type "C". Laboratory and field evaluations were conducted on laboratory animals, calves and late pregnant cows with monitoring the active and passive antibodies in vaccinated cows and their offspring respectively. Laboratory evaluation proved purity, safety and high efficacy of the vaccine without interference between different vaccine ingredients. Field evaluation gave satisfactory results when pregnant cows vaccinated at late stage of pregnancy with high neutralizing antibody titers against BRV, BCV and C. perfringens as well as high E. coli agglutinating titers. Maternal immunity passively protected offspring during the critical period of age and remained protected till the end of sampling time (30th day post parturition).

Beef longissimus dorsi steaks were treated with 10, 25, and 50-kGy gamma irradiation and weekly examined during refrigeration storage at 5ºC to evaluate the changes in their organoleptic, bacteriological, chemical and nutritional quality characteristics as well as deterioration criteria. The signs of spoilage became apparent after 17 days of refrigeration storage in control untreated samples compared with 52 days for 10 kGy treated samples; however, samples treated with 25 or 50 kGy remained without signs of spoilage until the end of storage period (4 months). A characteristic burnt flavor was distinguished in irradiated beef samples, which was intensified with high irradiation dose, but decreased during storage. High doses of irradiation especially 50 kGy resulted in a brownish color of meat surface. Moreover, gamma irradiation resulted in high thiobarbituric acid values after treatments and during storage due to lipid oxidation. Thiamin content of beef was severely reduced and the reduction was dependant on the irradiation dose. Riboflavin was also affected by irradiation, but it was much stable than thiamin. The proximate chemical composition of beef was slightly affected by irradiation.

In this study, two methods for determination of formalin amount were applied on samples of inactivated vaccines representing local or foreign companies. The first method; matching method was conducted by using phenyl hydrazine while in the other method is; spectrophotometry phloroglucinol was used. Spectrophotometrical method was found more sensitive and more accurate than the matching one. At the same time, the spectrophotometry method could be used for determination of formalin in all inactivated vaccines either bacterial or viral vaccines.

The challenge virus standard (CVS-11) strain of fixed rabies virus was propagated in weaning mice brains and in suckling mice brains. It was also propagated on baby hamster kidney cell line (BHK-21) with use of diethylaminoethyl-dextran (DEAEDextran). These passages were titerated in 3-4 weeks old white Swiss mice using mouse inoculation test (MIT). The virus harvest was concentrated using zinc acetate method , inactivated by beta-propiolactone (BPL) and adjuvanted with combination of vitamin E and selenium. The prepared adjuvanted inactivated tissue culture rabies vaccine was subjected to quality control tests as safety, sterility and potency using National Institute of Health (NIH) test against reference vaccine.

Peroxidase labeled immunoglobulins to camelpox virus (CPV) were prepared for use in various techniques of ELISA. Ten rabbits and three goats were inoculated with a mixture of camelpox virusand Freund’s adjuvant. Sera were pooled separately on the 10th day post the last inoculation and immunoglobulins were precipitated using saturated ammonium sulphate. The globulins were 2.8 g/dl and 2.5 g/dl for rabbits and goats respectively and used for peroxidase conjugation. The peroxidase labeled immunoglobulins were titrated and evaluated using direct solid phase ELISA, double antibody sandwich ELISA and dot immunoblot ELISA. The prepared conjugates gave specific and clear positive reactions till the dilution of 2000 and 1500 for rabbits and goats immunoglobulins respectively. The prepared labeled immunoglobulins could be successfully used in detection of camel pox viral antigen of local virulent and standard vaccinal strain of the virus using various ELISA techniques.

In this study we used one reference Climson University (CU) strain and 3 virulent field strains isolated from naturally infected chicken and identified as P. Multocida. DNA was extracted from all strains and subjected to restriction endonuclease analysis, using EcoRI, HpaII and Hind III revealing that, great similarity between either the reference or local virulent field isolates. The obtained results indicated that the most differentiable restriction endonuclease enzyme was the Hind III, which showed different band patterns between different strains.

To analyze the major outer membrane proteins (OMPs) of the sensitive or resistant Pseudomonas aeruginosa strains, the OMPs were separated from the cellular elements by sarcosyl extraction method. OMPs profiles were conducted by SDSpolyacrylamide gel electrophoresis. Amoxicillin clavulanic acid (AMC) sensitive P. aeruginosa serotype K showed four protein bands; 35.713, 31.159, 26.107 and 22.869 KD. While AMC sensitive P. aeruginosa serotype H showed three bands of 35.713, 27.164 and 23.174 KD. Whereas AMC resistant P. aeruginosa serotype G, that was positive for the blaTEM gene by the PCR, modified its protein pattern. It has five protein bands of 52.142, 38.525, 30.690, 27.164 and 22.569 KD. These findings suggested that blaTEM gene and the outer membrane protein barrier are contributed to the resistance to amoxicillin clavulanic acid in P. aeruginosa. To determine a possible relationship between the resistance of P. aeruginosa and the production of antibodies against its outer membrane protein, antibodies against OMPs of AMC sensitive and resistant P. aeruginosa strains were prepared in mice and evaluated by ELISA. Our results showed that there was no association between immunogenicity of the outer membrane proteins and resistance of P. aeruginosa to antibiotics.

Evaluation of amitraz against ticks and mites infestation in cattle and sheep in comparison with diazinon and deltamethrin was performed. Amitraz showed over 95 % inhibition of oviposition and hatching of laid eggs at dilution of 1:500 while diazinon and deltamethrin produced around 90 % inhibition of oviposition at the same dilution. Fed ticks were more susceptible for all tested acaricides than the unfed ticks, where amitraz reached its full effectiveness (100 % kill of fed and unfed) 2 weeks after application while diazinon and deltamethrin produced over 90 % at the same dilution. Spraying application of amitraz 12.5 % resulted in 100 % tick control by day 5 and the effect was maintained for further 28 days whereas diazinon and deltamethrin were fully effective by days 9 and 13, respectively and their efficacy were maintained for 16 and 20 days, respectively. Spraying application of amitraz 12.5 % produced 100 % efficacy as no live mites were found on day 17 and maintained in full effectiveness till day 33 where respraying was needed. In conclusion, amitraz produced rapid detachment of ticks from animals; its residual effect was long and protected animals from re-infestation for 29 days and was able to eradicate psoroptes mite infestation in sheep.