Isospora suis Enteritis in Piglets

Abstract

Abstract. A species of porcine coccidia, Zsospora suis, when inoculated into piglets, produced diarrhea, dehydration, weight loss and death. Gross lesions were characterized by a fibrinonecrotic membrane within the jejunum and ileum. Villous atrophy and variable erosion, often with an adhered necrotic membrane, were seen microscopically. Asexual and sexual stages of I. suis were seen within the intestinal epithelium and oocysts were recovered from the feces. The seventy of clinical disease and lesions were dose-related.In 1934, researchers recognized pig diarrhea and enteritis associated with coccidia and identified a new species of porcine coccidia as Isospora suis [2]. The oocysts of eight species of Eimeria and one species of Isospora in swine have been described [ 131. Although coccidia are widespread in the swine population [15], most authors have considered swine coccidia not to be of clinical importance [ I l , 141. With confinement swine facilities now a common husbandry practice, clinical coccidiosis has been seen more frequently [3, 5 , 101. Investigators at the Veterinary Diagnostic and Investigational Laboratory at Tifton, Ga., have described in piglets a clinical and pathologic entity associated with coccidiosis [lo]. In 1978, sporulated oocysts of I. suis were recovered from 23 (49%) of 47 clinical cases studied. Oocysts of I. suis were given to five litters of piglets in an attempt to reproduce the disease seen by practitioners and the laboratory diagnosticians. Materials and MethodsThe original I. suis inoculum was obtained from a 10-day-old piglet with clinical coccidiosis from which only oocysts of 1. suis were recovered. Feces from this piglet were placed in 2.5% potassium dichromate in petri dishes or aerated flasks for 3 to 5 days for sporulation of oocysts. The fecal suspension was passed through wire mesh sieves, centrifuged at 1,500 rpm for 5 minutes, and the supernatant discarded. The oocyst pellet was resuspended in Sheathers sugar solution (1 2 9 specific gravity) and the oocysts harvested, washed in water to remove potassium dichromate and sugar and counted with a hemacytometer. Ten of 12 counts (discarding high and low counts) were averaged and the dose calculated. These sporulated oocysts were passed through young pigs shown to be negative for coccidial oocysts in the feces. The pigs were maintained in individual wire bottom cages and used to obtain oocysts to dose litters 1 and 2. Subsequent litters (3,4 and 5) were dosed with I. suis oocysts from these pigs and from piglets of litters I and 2.

The role of Isospora suis in the ethiology of diarrhoea in suckling piglets

“…The importance of Isospora suis as a primary pathogen in the onset of suckling piglet diarrhoea was shown in several trials (Stuart et al, 1980;Robinson et al, 1983;Harleman et al, 1984;Vitovec et al, 1990) and it was confirmed by this field experience of ours. The results of performed fecal-microscopic, bacterio- T0 T1 T2 T3 logical and virological examinations gave a clear evidence of the correlation between diarrhea and presence of Isospora suis.…”

Isospora suis: an experimental model for mammalian intestinal coccidiosis

“…suis is one of the most common enteropathogens of piglets and also the most intriguing parasite in terms of its population dynamics and biology (Martineau and del Castillo 2000). In earlier studies of experimental infections of piglets, different infection doses ranging from 3×10 3 to 1×10 6 oocysts/piglet, and different time points of infection (from the first day to the sixth week of life) have been used to study excretion dynamics, pathology and dose/age relationships (Stuart et al 1980(Stuart et al , 1982Robinson et al 1983;Meyer 1984, 1985;Koudela 1987, 1990;Vítovec et al 1991;Blagburn et al 1991;Kučerová 1999, 2000;Bach et al 2003). High doses and infections on the first day of life cause significant morbidity (Stuart et al 1980(Stuart et al , 1982, and this effect is even more pronounced in the presence of other pathogens such as rotavirus (Vítovec et al 1991).…”

“…In earlier studies of experimental infections of piglets, different infection doses ranging from 3×10 3 to 1×10 6 oocysts/piglet, and different time points of infection (from the first day to the sixth week of life) have been used to study excretion dynamics, pathology and dose/age relationships (Stuart et al 1980(Stuart et al , 1982Robinson et al 1983;Meyer 1984, 1985;Koudela 1987, 1990;Vítovec et al 1991;Blagburn et al 1991;Kučerová 1999, 2000;Bach et al 2003). High doses and infections on the first day of life cause significant morbidity (Stuart et al 1980(Stuart et al , 1982, and this effect is even more pronounced in the presence of other pathogens such as rotavirus (Vítovec et al 1991). Since we tried to mimic a natural infection, we chose a comparatively low dose of infection (1×10 4 oocysts/piglet) on the third day of life, a time point when piglets seem to regularly become naturally infected in the field (for review, see Lindsay et al 1992).…”

Pharmacokinetics of Toltrazuril and Its Metabolites, Toltrazuril Sulfoxide and Toltrazuril Sufone, after a Single Oray Administration to P1gs

“…Isospora suis is one of the most prevalent parasites in intensive pig production causing significant economic losses due to transient diarrhea in young piglets with subsequently decreased weight gain and poor performance [12,14,15].…”