Epidemiological Survey and Sero-Grouping of Type-Strains of Leptospirosis in the Vertebrate Animal in Pakistan

Abstract

Before arriving at any conclusion as to the significance of leptospirosis, Brucellosis and vibriosis in causing disease conditions in animal and man, on the basis of the present study, it must be borne in mind that: 1. The number of samples/animals examined was not large enough to make generalized deductions. 2. The samples had been collected from particular category of animals, viz., animal with breeding problems and therefore, the sampling was not random. As such it would not be justifiable to generalize the conclusions. The above limitations do not however, minimize the role, significance or possible involvement of three infections in various breeding problems studied. The main conclusions are summarized as under: I. LEPTOSPIROSIS i. The incidence of leptospirosis (based on the presence of specific leptospira agglutinins in the blood serum) in buffalo-cows was 45.31%. The bulls of S.P.U. had 28.26% positive animals. The overall incidence in buffaloes (male and female) was 43.77%. ii. The incidence of leptospirosis in cattle-cows was 48.65% of S.P.U. bulls, 22.22% were positive and the overall incidence in cattle (male and female) was 48.65%. iii. The incidence of leptospirosis was higher in rice growing areas (Buffaloes-56.00%; cattle-68.52%) with Gujrawala having an incidence of 58.33% in buffaloes and 82.50% in cattle as compared to its incidence in non-rice growing areas (buffaloes-36.93%; cattle-41.80%). iv. In the human population, the incidence in Lahore Metropolitan area in the higher income group, was mil. In the sadhoke rural area (rice-growing area) 20.83% of the human population examined had leptospira agglutinins in their blood sera. v. Majority of the positive samples (Buffaloes-87.84% cattle-97.24%) gave positive reactions to leptospira pool III antigens. Almost all pool III positive samples gave 3+ reactions to serotypes autumnalis, conicola and icterohaemorrhagiae antigens. A few samples gave 2+ agglutinination reactions to Serotype pyrogenes. II. BRUCELLOSIS i. The incidence of brucellosis (based on the presence of Brucella agglutinins in sera) in buffaloes-cows was 2.06% and in cattle-cows, it was 2.69%. All bulls of S.P.U. were negative for the presence of Brucella agglutinins. The animal at “Farms” had higher incidence (buffaloes-cows-5.80%; cattle-cows-5.45%) as compared to its incidence in villages (buffaloes-cows-0.89%; cattle-cows-1.53%). This may be due to differing environmental and management conditions in the two areas. ii. The human population in Lahore metropolitan area and sadhoke rural area did not have any Brucella agglutinins in their blood sera. III. VIBIOSIS i. The incidence of vibriosis in buffaloes-cows was 1.93% of the animals examined while in cattle-cows, 12.56% vaginal mucus samples gave positive agglutination reactions to vibrio foetus antigens. The low incidence of infection in buffaloes-cows may be an indication that perhaps these animals are resistant to infection with vibrio foetus strains I & IV. ii. 9.18% buffalo-cow and 7.90% cattle-cow vaginal mucus samples gave doubtful reactions to vibrio foetus antigens. These reactions may be an indication of presence of vibriosis in the herd or else may indicate reactions due to infections with vibrio bubulus which was found present in all bufaloo-bulld and 2 out of 9 cattle-bulls examined. Diseases as causes of Abortion/premature Births/Breeding problems Abortion/premature births I. Leptospirosis i. In buffalo-cows, the percentage of abortions in leptospira positive (1.27% animals) was not significantly different from percentage of abortions in leptospira negative (1.92) animals. Leptospira, therefore did not seem to be particularly involved in buffalo-cows examined. ii. In cattle-cows, 12.75% leptospira positive animals had histories of abortions while 5.38% leptospira negative animals had similar gistories. Based on these figure it has been estimated that leptospirosis may be responsible for 45.36% of all recorded abortions in cattle-cows examined. II/III. Brucellosis and Vibriosis i. In buffalo-cows both brucellosis and vibriosis did not seem to be particularly related to abortion/premature births. ii. In cattle-cows, both leptospirosis and brucellosis could equally be responsible in few cases of abortions recoded in farms. iii. Vibriosis did not seem to play a significant role in abortions although in district Gujrawala, in at least two cattle-cows with histories of abortions vibriosis seemed more involved. B. Anaestrous and Repeat Bleeding I. Leptospirosis i. In buffalo-cows 14.81% serum samples from anaestrous animals had leptospira aggulinins while 45.24% serum samples from repeat bleeding animals were positive for leptospirosis. This is significant difference. ii. In cattle-cows, there was no significant difference in the incidence of leptospira in anaestrous 50% and in repeat breeding 54.78%. II. Brucellosis Both in buffalo-cows and cattle-cows none of the serum samples from anaestrous animals had brucellosis in them, while in repeat bleeding animals 2.43% buffalo-cows and 3.31% cattle cows serum samples were positive for brucellosis. There are very low incidence rates in both species and do not present any significant difference in two groups. III. Vibriosis In buffalo-cows and cattle cows, vaginal mucus samples from anaestrous animals were negative for vibriosis. In repeat breeding buffalo-cows only 1.08% samples- a non-significant percentage gave positive reactions to vibriosis. In cattle cows 13.36 samples were positive from vibriosis.