Bacteriological examination of 70 nesting green turtles (Chelonia mydas) from Tortuguero National Park, Costa Rica was performed to investigate nasal and cloacal aerobic bacteria. A total of 325 bacterial isolates were obtained, including 10 Gram-negative and three Gram-positive genera. Two hundred thirty-nine were Gram-negative and 86 were Gram-positive isolates. Klebsiella pneumoniae was the most common microbe identified in turtle samples: 27/70 (38.5%) in cloacal, and 33/70 (47.1%) in nasal samples. The Enterobacteriaceae family, including Enterobacter agglomerans, E. cloacae, Escherichia coli, Klebsiella oxytoca, K. pneumoniae, and Serratia marcescens, was the largest Gram-negative group of bacteria recovered and comprised 127 of 239 (53.1%) of the Gram-negative isolates. Staphylococcus species was the largest Gram-positive bacteria group, including S. aureus, S. cromogenes, S. epidermis, and S. intermedius, and made up 63 of 86 (73.2%) of the Gram-positive isolates recovered. The results of this study demonstrate that the aerobic bacterial flora of nesting green turtles at Tortuguero National Park is composed of a very wide spectrum of bacteria, including several potential pathogens.

A case-control study of calves under 3 months of age was carried out by weekly visits to 15 farms in the canton of Tilarán, Costa Rica. Most farms were dedicated to beef or dual-purpose (DP) production. Faecal samples were collected over a 6-month period from a total of 194 calves with clinical signs and from 186 animals without clinical signs of diarrhoea as assessed by a scoring system. The samples were investigated for the presence of viruses, bacteria and parasites. Torovirus was detected for the first time in Costa Rica and was present in 14% of calves with diarrhoea and in 6% of the controls. Coronavirus and Rotavirus were less frequently encountered in either one of the groups (in 9 and 7% of scouring calves and in 1 and 2% of controls, respectively). Escherichia coli was detected in 94% of all the faecal samples, but isolates from only three samples from calves with diarrhoea contained the K99 antigen. Similarly, Salmonella was found only in scouring calves. Cryptosporidium oocysts were detected in animals with signs of diarrhoea, while other coccidia oocysts, Strongylida and Strongyloides eggs were frequently found in animals both with and without diarrhoea. A conditional logistic regression (CLR) analysis to compare healthy and scouring calves showed a significant difference with regard to the presence of Torovirus, Rotavirus and Coronavirus.

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The use of avoparcin as a growth promoter is considered to have selected for vancomycin-resistant enterococci (VRE). In Costa Rica, the use of avoparcin for poultry and swine was intensive until the product was withdrawn from the market in 2000. We evaluated the presence of VRE in poultry, swine, and cattle fecal samples obtained during 1998 and 1999. A total of 185 VRE isolates were recovered from 116 out of 893 samples. Enterococcus faecium was the most frequently isolated species (50.8%), being predominant among poultry (71.6%) and swine (37.7%) isolates, but it was not recovered from the bovine samples. The secondmost-frequently-isolated species from poultry and swine, respectively, were E. durans (23.2%) and E. faecalis (21.7%). E. casseliflavus was the only species obtained from bovine samples, but it was not found among the avian isolates. An evident predominance of the vanA determinant among vancomycin-resistant enterococcal species from poultry and swine, but not from cattle, was observed and was similar to the situation in European countries before avoparcin was forbidden. The diversity of the vanA determinant in the isolates was assessed by detection of the IS1251 insertion in the vanSH intergenic region and of the IS1476 insertion in the vanXY intergenic region. However, in none of the 154 vanA ؉ isolates recovered in this study were those insertions detected.

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The microflora associated to furuncular lesions, larvae and pupae of Dermatobia hominis, as well as the relationships between parasite, host and microflora associated, as a comprehensive microsystem, has been studied. One hundred and two furuncular myiasis due to D. hominis larvae in several breeds of cattle were studied and the following bacterial species were significant: Staphylococcus aureus, S. epidermidis, S. warneri, Bacillus subtilis and Escherichia coli. Closely related, the microflora associated to 141 samples from first, second, third instar larva and both external surface and larval cavities has been studied. The representative associated microflora to the larvae were: S. aureus, B. subtilis, S. hycus and Moraxella phenylpiruvica, Moerella wisconsiensis, Proteus mirabilis and P. vulgaris, M. phenylpiruvica, M. wisconsiensis, P. mirabilis and P. rettgeri were the representative microflora associated to 64 pupae of D. hominis.

We studied eight different myiasis of sheep caused by screwworm flies under laboratory conditions. Swabs were taken from the wound, before, during, and after the myiasis. Seven hundred and thirty-one samples were streaked on different bacteriological media. All samples were identified by Api System (bioMerieuex). We found thirty-eight different bacterial species in the exudates from the myiasis (before, during, and after the parasitic cycle). The analysis of bacterial flora of the screwworm showed, on larvae stage 1, 10 different bacterial species, on larvae 2, 12 bacterial species; larvae 3, 15 bacterial species; crawl off, 15 bacteria species, pupa, 9 bacterial species; and adults, 2 bacterial species and on the pioneer fly, 14 different bacterial species were isolated and identified.

Hird, D., Pdrez, E., Caballero, M., Rodriguez, L. and Velfizquez, J., 1990. Identification of selected disease agents from calves on Costa Rican tropical cloud-forest dairy farms. Prev. Vet. Met., 231.Rotavirus, K99+ E. coli and coccidia were identified from feces of 10%, 13% and 37% of 300 selected dairy calves ~< 3 months of age, and from 26%, 36% and 45% of 42 Costa Rican dairy farms, respectively. Calf breeds were Holstein 68%, Jersey 27% and other breeds 5%. Median calf ages at identification of rotavirus, K99 + E. coli and coccidia were 14.5, 15, and 33 days, respectively. Differences between isolation rates for the wet and dry season were not statistically significant for any of the three agents. Prevalence of antibodies against infectious bovine rhinotracheitis and bovine parainfluenza-3 virus were 7% and 82%, respectively, for selected calves. Of calf sera tested for immunoglobulins, 9.5% were negative.