Salmonellosis in calves without intestinal lesions

Abstract

Salmonellosis is a known cause of enteric disorders in calves. However, cases in the septicemic form may not present enteric lesions, which may lead the veterinary practitioner to not suspect salmonellosis, compromising the diagnosis. The current study describes the epidemiological, clinical, pathological and immunohistochemical aspects of septicemic salmonellosis in calves without enteric lesions. The protocols involving bovine material submitted to the Pathology Laboratory (LAP) of the “Faculdade de Medicina Veterinária e Zootecnia” (FAMEZ) of the “Universidade Federal do Mato Grosso do Sul” (UFMS) from January 1995 to July 2018 were studied. Cases confirmed or suggestive of septicemic salmonellosis in calves without enteric manifestations were selected. Fragments of the liver, lung, and spleen embedded in paraffin were submitted to immunohistochemistry (IHC). Only cases in which there was positive marking on the IHC or culture isolation of Salmonella were included in this study. Of a total of 5,550 cattle examined in the period, ten presented septicemic salmonellosis without enteric lesions. Clinical signs included mucosal pallor, apathy, hyperthermia, and dyspnea. Only three calves presented diarrhea, and two were found dead before clinical changes were observed. The most common necropsy findings were hepatosplenomegaly; yellow, orange or brown discolored livers; pale mucous membranes; inflated and sometimes red lungs; fibrin or fluid within body cavities; and gallbladder filled with inspissated bile. Jaundice was observed in three calves that had a concomitant infection with Anaplasma sp. Microscopically, paratyphoid hepatic nodules and interstitial pneumonia were the most frequent manifestations, followed by thrombosis and bacterial colonies in the spleen, lung, liver, and brain. A strong positive marking was observed in IHC, predominantly in the lung and to a lesser extent in the liver. Polymerase chain reaction (PCR) indicated the Dublin serotype as the causative agent in the samples of the four calves submitted to this procedure. In calves, the septicemic form was the major cause of death due to salmonellosis. Septicemic salmonellosis was usually not accompanied by diarrhea. The clinical signs of septicemia are nonspecific and of little assistance in the diagnosis. IHC has been shown to be efficient in the detection of the agent, mainly in the lung and especially in situations where it is not possible to perform bacterial culture.

Epidemiological and clinicopathological findings in 15 fatal outbreaks of salmonellosis in dairy calves and virulence genes in the causative Salmonella enterica Typhimurium and Dublin strains

“…Similar samples were proposed by Holschbach and Peek [31]. In accordance with Guizelini et al [32] and Ramos et al [35], the main macroscopic lesions observed in our work were enteritis with or without fibrin, mesenteric lymphadenomegaly, and hepatomegaly. In contrast to what was reported by Pecoraro et al [17], in our work, macroscopic lesions in the lungs and spleen were less frequent.…”

“…Additionally, in all S. Dublin cases, macroscopic intestinal lesions were absent, and calves did not show diarrhea except for one case. Similar results were observed by Guizelini et al [32] in Brazil. Assays performed with this serotype have shown that the aflagellated types isolated from the bloodstream can generate a lower intestinal inflammatory response and increased invasiveness [9].…”

“…The Dublin serotype was detected in 5 calves of 50 to 60 days of age from 4 outbreaks in which sudden death was the main reason for consultation. Recently, septicemic salmonellosis caused by S. Dublin in 1-to 3-month-old calves was described in Uruguay and Brazil [8,32,33]. On the other hand, in the pathogenesis of digestive disease caused by Typhimurium serovar, animals show an enteric inflammatory process that ultimately leads to diarrhea [34].…”

Outbreak investigation of septicemic salmonellosis in calves

“…The results of this study and previously cases [1,19] show that septicemic salmonellosis is endemic in Brazil and may cause high losses to the livestock. Due to its zoonotic character, in our country, salmonellosis is a disease that has official surveillance guidelines only in aviculture [20], despite its also being a potential cause of economic losses in beef cattle.…”

Silver nanoparticle effect on Salmonella enterica isolated from Northern West Egypt food, poultry, and calves

“…According to the WHO, since 1990, Salmonella Enteritidis has been considered the most common cause of gastroenteritis worldwide (Chaitram et al 2003 ) and salmonellosis in bovine, ovine, and poultry (Suh and Song 2006 ; Firoozeh et al 2012 ; Dutta et al 2012 ; Guizelini et al 2019 ).…”