Clinicopathological Indications of Resilience of Swamp Buffaloes to Infection with Fasciola gigantica
Fasciolosis caused by Fasciola gigantica is a common disease among livestock such as swamp buffaloes (Bubalus bubalis) in rice-producing areas in humid tropical regions. It causes a significant reduction in meat and milk production, growth rate, fertility and draught power in infected animals (Dargie, 1987). However, the extent to which infection adversely affects the production of infected animals depends on several factors, among which is the breed of susceptible animals. Different breeds of animals and individuals within the same breed manifest varying responses and resilience to infection (Spithill et at., 1999). For instance, differences in response to infection with F. gigantica were seen in Bali, Ongole and buffalo calves in terms of weight gain (E. Wiedosari, personal communication, 1997). This information demonstrates breed differences in response to F. gigantica infection and shows that swamp buffaloes are more resilient than cattle to F. gigantica. The clinicopathological responses of swamp buffaloes naturally infected with F. gigantica were evaluated in this study to determine whether these parameters would indicate resilience to natural infection with parasites.
Comparative Parasitological and Haematological Changes in Two Breeds of Sheep Infected with Fasciola gigantica
Twelve each of Red Masai and Dorper sheep, aged between 6 and 9 months, were acquired from a Fasciola-free area of eastern Kenya. Each breed was divided into two groups of 6. The sheep in one group of each breed were experimentally infected with 400 viable metacercariae of Fasciola gigantica. The other group of 6 sheep of each breed remained as uninfected controls. The animals were monitored regularly for any evidence of disease. Blood samples taken weekly revealed a general reduction in red cell counts and packed cell volume, which was much faster in the infected Dorper sheep than in the Red Masai. This reduction started from the tenth week after infection and persisted to the end of the experiment 18 weeks post infection (PI). The absolute eosinophil counts rose in all the infected animals, but the values were higher among the Dorper than among the Red Masai. Patency occurred at weeks 12 and 13 PI in the Red Masai and Dorpers, respectively, with the latter shedding significantly more fluke eggs. The worm recovery rates were higher among the Dorpers than among the Red Masai, though not significantly so. On the basis of egg counts and clinicopathology, the Dorper sheep were considered to be more susceptible to F. gigantica infections.
Synergistic Effect of High Temperature and High pH on the Destruction of Salmonella enteritidis and Escherichia co1i O157:H7.
This study was undertaken to determine if high temperature and high pH interact synergistically to enhance the rate of destruction of two important gram-negative foodborne pathogens, Escherichia coli O157:H7 and Salmonella enteritidis . The rates of destruction in NaHCO3-NaOH buffers at pH 7.0, 10.0, and 11.0 were determined at 35, 40, 45, 50, 55, 60, and 65°C. Use of an improved heating protocol eliminated a "tailing effect" at longer exposure times. The present study demonstrated that the combination of high pH and high temperature resulted in a highly significant synergistic interaction (P > F = 0.0001), which caused rapid death of both E. coli O157:H7 and S. enteritidis . This "alka-therm" technology might be used commercially to destroy gram-negative foodborne pathogens on various raw agricultural commodities.