Mouse-to-mouse transmission of infections with <i>Giardia muris</i>

SUMMARYThe transmission of infection with Giardia muris among CD-I mice was quantified by determining the duration of the latent period and intensity of cyst release during the acute phase of the infection. Housing of experimentally inoculated mice with uninfected mice in the same cage resulted in 100% transmission of infection. The dissemination of the infection was faster if experimentally inoculated hosts were passing high numbers of cysts at the time of housing with uninfected animals. The course of ‘naturally’ acquired and experimentally induced infections was similar. We conclude that G. muris has a high transmission potential and that the number of cysts randomly consumed does not influence the course and eventual outcome of the infection.</jats:p

Importância de Cryptosporidium spp. como causa de diarréia em bezerros Importance of Cryptosporidium spp. as a cause of diarrhea in calves

Avaliou-se a presença de oocistos de Cryptosporidium spp. em amostras de fezes de 14 bezerros e de suas mães até a oitava semana pós parição. A maior taxa de excreção de oocistos foi verificada em bezerros com sete dias de idade. Das vacas, 42,8% foram positivas para Cryptosporidium no período pós-parto. Em outra etapa deste estudo, foram acompanhados 57 bezerros positivos para Cryptosporidium, com até 30 dias de idade, provenientes de 32 propriedades leiteiras, e estudouse o grau de eliminação dos oocistos com a possível ocorrência de diarréia. Em todos os animais positivos para Cryptosporidium foi pesquisada a presença de bactérias enteropatogênicas, vírus (Rotavirus e Coronavirus) e protozoários (Eimeria spp.).<br>The aim of this research was to evaluate the shedding of Cryptosporidium spp. oocysts in fecal samples from 14 calves from one dairy farm, from birth until 60 days old and from cows until eight weeks after parturition. The higher percentage of oocysts excreted was observed in 7-day-old calves. In the post-partum period 43.7% of cows were positive for Cryptosporidium oocysts. Further analyses were accomplished in 57 calves from another 32 milk farms, previously known as positive for Cryptosporidium, through oocysts fecal screening and clinical signs analyses until calves were 30 days old. Fecal samples from all animals that presented diarrhea were screened for the presence of bacteria, virus (Rotavirus and Coronavirus ) and protozoa (Eimeria spp.)