Aim:  To develop a probiotic with effectiveness against Aeromonas sp., which was pathogenic to rainbow trout. Methods and Results:  When Bacillus subtilis AB1, which was obtained from fish intestine, was administered for 14 days to rainbow trout in feed at a concentration of 107 cells per gram either as viable, formalized or sonicated cells or as cell‐free supernatant, the fish survived challenge with the pathogen. AB1 stimulated immune parameters, specifically stimulating respiratory burst, serum and gut lysozyme, peroxidase, phagocytic killing, total and α1‐antiprotease and lymphocyte populations. Conclusions:  Bacillus subtilis AB1 was effective as a probiotic at controlling infections by a fish‐pathogenic Aeromonas sp. in rainbow trout. Significance and Impact of the Study:  Disease control in fish is possible by means of the oral application of live and inactivated cells and their subcellular components with the mode of action reflecting stimulation of the innate immune response.

In Trinidad, Tilapia (Oreonchromis spp.) is one of the most important fresh water food fish and the number of farms has been increasing annually. A study was conducted in the local tilapia industry to determine the microbial quality of pond water, prevalence of bacterial pathogens and their anti-microbial resistance using the disk diffusion method. Seventy-five apparently healthy fish and 15 pond water samples from three of the four commercial tilapia fish farms in the country were processed. The 202 bacterial isolates recovered from fish slurry and 88 from water, belonged to 13 and 16 genera respectively. The predominant bacteria from fish slurry were Pseudomonas spp. (60.0%), Aeromonas spp. (44.0%), Plesiomonas (41.3%) and Chromobacterium (36.0%) (P < 0.05; chi(2)) compared with isolates from pond water where Bacillus spp. (80.0%), Staphylococcus spp., Alcaligenes spp. and Aeromonas spp. (60.0%) were most prevalent (P < 0.05; chi(2)). Using eight anti-microbial agents, to test bacteria from five genera (Aeromonas, Chromobacterium, Enterobacter, Plesiomonas and Pseudomonas), 168 (97.1%) of 173 bacterial isolates from fish slurry exhibited resistance to one or more anti-microbial agents compared with 47 (90.4%) of 52 from water (P > 0.05; chi(2)). Resistance was high to ampicillin, 90.2% (158 of 173), erythromycin, 66.5% (115 of 173) and oxytetracycline, 52.6%, (91 of 173) but relatively low to chloramphenicol, 9.8% (17 of 173) and sulphamethoxazole/trimethoprim, 6.4% (11 of 173) (P < 0.05; chi(2)). For pond water isolates, the frequency of resistance across bacterial genera ranged from 75% (nine of 12) for Chromobacter spp. to 100% found amongst Enterobacter spp. (six of six), Plesiomonas spp. (nine of nine) and Pseudomonas spp. (eight of eight) (P < 0.05; chi(2)). Resistance was generally high to ampicillin, 78.8% (41 of 52), erythromycin, 51.9% (27 of 52) and oxytetracycline, 34.5% (18 of 52) but low to sulphamethoxazole/trimethoprim, 7.7% (four of 52) and norfloxacin, 3.8% (two of 52) (P < 0.05; chi(2)). It was concluded that the rather high prevalence of bacterial pathogens in tilapia along with their high prevalence of resistance to anti-microbial agents might pose therapeutic problems as well as health risk to consumers. The microbial presence and their anti-microbial resistance in the tilapia industry are being reported for the first time in the country.

The present paper reviews the information available concerning the biology and transmission ecology of the African bovine species Schistosoma bovis, S. mattheei, S. margrebowiei and S. leiperi. Criteria for species identification (egg morphology, intermediate host spectra, definitive host-parasite relationships, etc.) are listed and the geographical distribution of the four species and factors determining the relative occurrence within their overall distributional ranges are described. S bovis and S. mattheei occur north and south of 10 degrees S, respectively, and S. margrebowiei occurs mainly, and S. leiperi only, in southern central Africa. Definitive host-related factors (susceptibility, water contact pattern, ect.) providing the background for being a primary definitive host and the primary definitive host spectra for the four schistosome species are described. The primary definitive host spectrum for S. margrebowiei and S. leiperi comprise lechwe, puku and waterbuck, for S. mattheei lechwe, puku, waterbuck plus cattle, and for S. bovis cattle and possibly also some of the listed antelope species. In addition, wild bovines and cattle may provide a reservoir of S. mattheei and S. margrebowiei in humans, but wild bovines and domestic stock play no major role in the transmission of other human species of schistosomes. The intermediate snail host spectra of S. mattheei and S. leiperi only comprise members of the Bulinus africanus species complex; S. bovis is transmitted by members of the B. truncatus, B. africanus and B. forskalii species groups, and S. margrebowiei is transmitted by members of the B. forskalii species group and possibly also by members of the B. tropicus and B. truncatus species groups. Factors determining the transmission ecology of the four schistosome species, and thereby the epidemiology of bovine schistosomiasis, are discussed. Influential factors comprise environmental conditions mediated via the effect of these on the size of the snail host population and on the rate of the intramolluscan development, behavioural patterns of the definitive host population and the course of the infection in the definitive host as related to aspects of susceptibility and level of endemicity. The epidemiological pattern (prevalence and intensity of infection, seasonality of transmission, etc.) is described and exemplified, and it is finally concluded that the increasing water conservation and changing methods of husbandry may result in bovine schistosomiasis becoming a major veterinary problem in Africa.

Arthropod-borne diseases are important causes of morbidity and mortality of companion animals in Trinidad. As clinical signs are vague, more sensitive methods to diagnose these diseases based on the polymerase chain reaction (PCR) followed by reverse line blot hybridization (RLB) of amplified products are being developed. An RLB of 14 oligonucleotide probes coupled with polymerase chain-amplified regions of 16S rRNA or 18S rRNA genes of hemoparasites from cats and dogs detected Ehrlichia canis, Anaplasma platys, Babesia canis vogeli, feline mycoplasmas ("Candidatus Mycoplasma haemominutum,"Mycoplasma haemofelis), and some unknown species within the Babesia/Theileria group and the Anaplasma/Ehrlichia tribe. Amplified products were obtained from blood samples collected from 348 dogs and 15 cats. Overall, hemopathogen DNA was detected in 92 (26.4%) dogs and six (40.0%) cats. E. canis (49, 14.1%) and feline mycoplasma (5, 33.3%) DNA were most frequently identified in dogs and cats, respectively. B. canis vogeli (1, 6.7%) and E. canis (1, 6.7%) were also detected in cats. Mixed infections of Anaplasma/Ehrlichia sp. and Babesia sp. were present in five (1.4%) dogs, while mixed infections of the feline mycoplasmas were present in two (13.3%) cats, one of which was also positive for E. canis. Pyrexia was significantly associated with a positive RLB result in dogs (P= 0.00, chi(2), 1 df). This is the first reported application of macro-arraying techniques to detect arthropod-borne hemopathogens of companion animals in the Americas and the first detection of DNA of B. canis vogeli and E. canis in cats in Trinidad.

A longitudinal study was conducted on selected livestock farms to determine the prevalence of enteropathogens in diarrhoeic and non-diarrhoeic animals. The enteropathogens assayed from faecal samples and rectal swabs were bacteria (Escherichia coli, Campylobacter spp. Salmonella spp. and Yersinia enterocolitica), parasites (coccidia, gastrointestinal nematodes and Cryptosporidium spp.) and viruses (group A rotavirus and parvovirus). The prevalence of the enteropathogens in various animal species was related to age and month of the year. Generally, younger animals presented a higher prevalence of infection by enteropathogens than older animals while most infections occurred between the months of January and April. Key-words: Bacteria. Viruses. Parasites. Diarrhea. Livestock.Resumo Um estudo longitudinal foi realizado em fazendas de criação selecionadas, para determinar a prevalência de enteropatógenos em animais com ou sem diarréia. Os enteropatógenos analisados de amostras fecais e swabs retais foram: bactérias (Escherichia coli, Campylobacter spp, Salmonella spp e Yersinia enterocolitica); parasitas (coccídeos, nematóides gastrintestinais e Cryptosporidium spp) e vírus (Rotavírus grupo A e parvovírus). A prevalência dos enteropatógenos em várias espécies de animais foi relacionada à idade e mês do ano. Geralmente, a prevalência de infecção por enteropatógenos foi maior entre os animais mais jovens que entre os animais mais velhos, enquanto a maioria das infecções ocorreu entre os meses de janeiro e abril.