Carlos Eduardo Real Pereira

Frequência e distribuição de Helicobacter spp. na mucosa gástrica de cães

Frequency and distribution of Helicobacter spp. in gastric mucosa of dogs The association of the helicobacter bacteria with gastric diseases in human beings and in some domestic pets and wild animals suggests these bacteria as a possible factor in the pathogenesis of gastritis in pet dogs. In this study we investigate the presence of Helicobacter spp. in the gastric mucosa of dogs and evaluate its association with some macro and microscopic findings, considering the age of the animals. Samples from cardia, fundus, body , and pylorus regions were collected from the stomach of 60 dogs for histopathologic examination, using hematoxilin-eosina (HE) and carbol-fucsina (CF) staining. The examinations detected Helicobacter spp. in 96.7% of the animals, revealing inflammatory infiltrate, predominantly mononuclear (100%), lymphoid nodules hyperplasia (98.3%), erosions/ulcerations (6.7%), hemorrhage (5%) and hyperemia (95%) in the samples stained with HE. There was no correlation between Helicobacter spp. infection and age of the animal, as well as between inflammatory changes and age in the presence of bacteria. Samples of the body and pylorus region showed increased presence of bacteria in the histopathologic

Lawsonia intracellularis in Pigs: Progression of Lesions and Involvement of Apoptosis:

The purpose of this study was to follow the progression of gross and histologic lesions and apoptosis events in Lawsonia intracellularis-infected enterocytes through the course of the disease, proliferative enteropathy (PE). Thirty 5-week-old pigs were divided into 2 groups: 20 challenged and 10 control animals. Groups of 3 pigs, 2 challenged and 1 control, were euthanized at 1, 3, 5, 8, 11, 15, 19, 24, 29, and 35 days after inoculation. Complete necropsies were performed with gross evaluation. Tissue samples from different sites of the gastrointestinal tract and other visceral organs were collected for routine histologic staining and for immunohistochemistry (IHC) for L. intracellularis. In addition, caspase-3, terminal deoxyuridine nick-end labeling assay, and electron microscopy were performed in ileum samples. Macroscopic and histologic lesions suggestive of PE were first detected 11 days after infection and continued through day 24. L. intracellularis antigen was first detected in the intestine by IHC on day 5 after inoculation, and the bacterium was first detected by transmission electron microscopy on day 15. Positive IHC staining for [L. intracellularis] and enterocyte proliferation, but no gross lesion, were detected on day 29. All 3 pigs euthanized on day 35 were grossly and histologically normal and IHC negative. Hyperplastic crypts in challenge pigs had more apoptotic cells on days 15, 19, and 24 postinfection (P < .05) compared to control pigs. Our results demonstrated the progression of lesions and infection by L. intracellularis and that inhibition of enterocyte apoptosis is not involved in the pathogenesis of proliferative enteropathy.

Evaluation of the involvement of mice (Mus musculus) in the epidemiology of porcine proliferative enteropathy

The aim of this study was to evaluate the fecal-oral transmission of L. intracellularis between mice and pigs. The study was divided into two parts. The first part aimed to determine whether mice could be infected by feces from pigs that are experimentally infected with L. intracellularis. Thirty-four Swiss mice received L. intracellularis PCR-positive feces from experimentally infected pigs (M1) for four consecutive days. Twelve other mice received swine negative feces (M2). Pools of mice feces were collected on alternating days post-exposure (dpe). The second part of the study aimed to test whether pigs could be infected when exposed to L. intracellularis PCR-positive feces from experimentally infected mice. Twelve 5-week-old pigs received feed mixed with L. intracellularis PCR-positive mice feces (P1), while the other two pigs received PCR-negative mice feces (P2) for four consecutive days. In the first study, the amount of L. intracellularis provided to M1 boxes per day was between 106 and 108. Mice shed, an average of 104 bacterial units every collection day. Three mice from M1 were positive for L. intracellularis by immunohistochemistry (IHC) at the end of the study. In the second part of the study, pigs in P1 received an average of 105 bacterial units per day. Ten pigs were infected by L. intracellularis based on positive qPCR and/or immunohistochemistry and serology results. These pigs shed an average of 104L. intracellularis/g of feces. Mice and pigs experimentally infected with L. intracellularis can infect each other, therefore, rodents should be considered players in the epidemiology of this disease in pig farms.