Muhammad Hassan Saleem

Epidemiological, Haematological & Serological Studies Of Leptospirosis In Dogs And Human At High Risk In And Around Lahore City - 2013

Leptospirosis is an important zoonosis of global importance capable of causing significant subclinical and clinical syndromes both in humans and animals. The disease is characterized by fever, vomiting, diarrhea, myalgia and other signs consistent with renal and hepatic disease. Considering the significance and the substantial losses rendered by Leptospirosis, the present project was designed to study epidemiology and haematology in dogs and humans at high risk in Lahore district and its peri-urban areas.
The study was accomplished in 4 phases. In phase-I, sero-prevalence both in dogs and human was studied including case fatality rate and associated risk factors through cross a sectional study. For this purpose, blood samples were collected from dogs attended at the Pet Centre of University of Veterinary and Animal Sciences, Lahore and other private clinics situated in and around Lahore area through systematic random sampling technique over a period of one year (1st Dec. 2010 to 30th Nov.2011). Blood samples from every fifth un vaccinated dog were collected, but if the dog was vaccinated then the sample was collected from the next unvaccinated one. In this phase 100 sera samples from human volunteers which were at maximum risk (veterinarian, pet and livestock owners, para-vet staff) were also collected. All samples were screened out by using ELISA kits like Canine Leptospira IgG ELISA Kit Catalog no. BG-CAN11485, NovaTein Biosciences, Woburn, MA, USA and Serion Elisa Plate, Virion/Serion GmbH, Wurzburg, Germany for dogs and humans respectively at the Medicine Laboratory and University Diagnostic Laboratory, University of Veterinary and Animal Sciences, Lahore.
To study overall prevalence of Leptospirosis in dogs a total of 429 dogs were examined and it was found that out of 429 blood samples 155 were found positive for Leptospira antibodies. Thus an overall prevalence of Leptospira was recorded as 36.13%. Prevalence of Leptospirosis in dogs during different months of the year was also recorded. The months of September, October and June showed ere the highest prevalence and recorded as 50%, 48.57% and 45% respectively. Although, a few cases were seen during the months of December, January and February while moderate number of cases was recorded during the rest months of the year. There was a significant difference (p<0.05) in the prevalence of Leptospirosis during the different months of the year. Out of these 429, 93 pups and 336 adults were examined for Leptospirosis and found that 26 pups and 129 adults were positive i.e. a prevalence rate of 27.95% (26/93) and 38.39% (129/336) for Leptospirosis was recorded in pups and adult dogs respectively and this difference was non-significant (p>0.05). In this study a prevalence rate of 38.49% (102/265) and 32.31% (53/164) for Leptospirosis was recorded in male and female dogs respectively and this difference between the sexes was also non-significant(p>0.05). According to the results of this study a sero-prevalence of 21.24% (24/113) in winter, 35.82% (24/63) in spring, 40.34% (71/176) in summer and 49.32% (36/73) were recorded in fall season and this difference was significant (p<0.05). The highest prevalence rate was observed in fall and summer seasons of the year during higher rain fall seasons of the year.
To study overall prevalence of Leptospirosis in humans, a total of 100 blood samples were examined through random sampling technique during the whole study period and overall prevalence rate of 44.00% was observed in human population. Different risk factors like different months of the year, age, sex and season were also studied and that the highest prevalence of Leptospira in humans was observed in the months of March, April and August i.e. 66.66%, 66.66% and 60.0% respectively. No significant difference (p>0.05) in the sero-prevalence of Leptospirosis in human during the different months of the year was observed. Sex-wise prevalence rate of 48.71% (38/78) and 27.27% (06/22) for Leptospirosis was recorded in male and female respectively and this difference was significant (p<0.05). The results of this research project revealed a prevalence rate of 47.29% (35/74) and 34.61% (09/26) for Leptospirosis in adults and young ones respectively and this difference was again non-significant (p>0.05). According to the results of this study a sero-prevalence of 41.93% (13/31) in summer, 40.00% (06/15) in fall and 25.92% (07/27) in winter, while 66.66% (18/27) was recorded in spring season of the year and this difference was significant (p<0.05) and the highest prevalence rate was observed in spring.
In phase-II, the effect of Leptospirosis on various blood parameters were determined in both dogs and human. The results of present study revealed a significant difference (P<0.05) between the Hemoglobin (Hb), Erythrocytic sedimentation rate (ESR), Packed cell volume (PCV), Total Leukocytic count (TLC), Neutrophils, Eosinophils and Monocytes of healthy and Leptospira affected dogs, while a non-significant difference was observed (P >0.05)among values of lymphocytes. It showed that values of Hb forthe diseased dogs were lower than healthy ones while ESR, PCV, TLC, Neutrophils, Eosinophils and Monocytes, were more than in normal dogs. Likewise, in humans all the studied parameters were significantly (P <0.05) different between infected and healthy ones. The values of Hb concentration in diseased humans were lower than the healthy ones while ESR, PCV, TLC, Neutrophils, Eosinophils, Basophils, and Monocytes were higher than in healthy people. A negligible change was observed in the percentage count of lymphocytes.
In phase-III, the comparative efficacy of commercially available vaccines against Leptospira was studied. Two commercially available vaccines, Vaccine #1 with protection against two serotypes of Leptospira (Canicola, Icterohaemorragiae) and vaccine #2with protection against four serovars of Leptospira i.e Canicola, Icterohaemorrhagiae, Grippotyphosa and Pomona were compared After six months it was observed through ELISA screening that the vaccine #2 provided better overall protection compared to the vaccine #1 to the pups as well as adult dogs against the Leptospirosis but this difference was non-significant (p>0.05).
In the last phase of this study the chemotherapy trial was conducted. Results found that the efficacy of Penicillin G was 70%, while in group B Amoxicillin produced 60% results and in group C Sarsaparilla proved to be 40% effective against this infection although this difference was non-significant (p>0.05). It is concluded that among therapeutic agents used to treat Leptospirosis in dogs, Penicillin G , Amoxicillin and Sarsaparilla are ranked in respective order of efficacies.



Phd. thesis

1588,T


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