[Association between amino acid sequences in peptide binding region [BOLA-DRB3] and susceptibility or resistance to calf diarrhea]

The major histocompatibility complex genes [mhc] encode MHC I and II molecules which present peptide fragments to T cells. Therefore these polymorphic molecules critically influence susceptibility to infectious diseases. At present study potential relationship between amino acid sequences in the antigen binding groove of different BoLA-DRB3 alleles and susceptibility or resistance to calf diarrhea was investigated. Twelve different DRB3 alleles were found among 171 calves [84 diarrheic and 87 healthy] analyesd by PCR-RFLP method. Amino acid sequences of the encoded peptide binding region were compared. 26 polymorphic positions were detected in this region. A significant association [p<0.05] was shown between occurrence of diarrhea and the presence of glutamic acid and tyrosine inpocket 4 and valine, glutamine and leucine in pocket 9 of peptide binding region. Thus it can be concluded that pockets 4 and 9 of the BoLA-DRB3 molecule would be involved in conferring susceptibility of calf to diarrhea

Cryptosporidia infection and associated bacterial entropathogens in diarrheic calves and cows in dairy farms around Tehran

Determination the effects of the bacterialentropathogens to increase infection of calves and cows tocryptosporidium. Descriptive study. A total of 152 calves and 300 cows. Microscopic detection of cryptosporidium inthe direct smears of feces samples from 3 farm in aroundTehran, using smears, fixing with methanol, staining withmodified zeal-nielson, detecting oocysts under a lightmicroscope with objective magnification of 40 X [at leastin 20 microscope field], confirming the observation usingmagnification of 100 X. on the other hand, feces sampleswere cultured for detection of bacterial agents such as:Salmonella, E. coli, Proteus, Klebsiella, Campylobacterand Pseudomonas as well as microscopic observation forpresence of acid-fast bacteria in the direct smears of feces. Descriptive statistics.In this study, Cryptosporidium was detected in40.78% of diarrheic calves of which 10.52% of cases hadcryptosporidium alone, and in 30.26% of casescryptosporidium was accompanied with at least one otherpathogenic bacteria. In 3.28% of cases acid-fast organismwas isolated alone. Target pathogens of this study wasisolated at least in 34.33% of feces samples of cows. In28% of cases Cryptosporidium was confirmed and in 5%acid-fast organism was observed. The results of the present study showed thatthe infection rates are significantly higher in calves than incows which may be the due to the age susceptibility toCryptosporidium. It is suggested that hygiene of calf den isof great importance