Experimental Cryptosporidiosis in Broiler Chickens

Abstract

Seven-day-old conventional broilers were inoculated either orally or intratracheally (IT) with 2.5 X 10(5), 5.0 X 10(5), or 2.0 X 10(6) oocysts of Cryptosporidium baileyi (32 birds for each dosage level per group; 192 birds total). Thirty-two birds served as unninoculated controls. Mean weekly weight gain and feed conversion were determined during a 5-week period. Carcass pigment was graded using a Roche Color Fan. Fecal oocysts were calculated from random cage samples 6, 8, 11, 13, 15, 18, 20, 22, and 25 days after inoculation (DAI). Effects of C. baileyi on immune responses were examined for Newcastle disease virus-hemagglutination inhibition (NDV-HI) antibody, infectious bursal disease virus-enzyme-linked immunosorbent assay (IBDV-ELISA) antibody titers and delayed hypersensitivity (DH) in half of the birds in each group. Disease or death from cryptosporidiosis did not result from oral inoculation of C. baileyi. Signs of respiratory disease, consisting of rales, sneezing, and dyspnea were observed in all IT-inoculated birds 7 to 21 DAI. Seven deaths occurred in the IT-inoculated groups 14 to 21 DAI. At necropsy, lung parenchyma was gray, firm, and wet in the ventral region. Air sacs contained a foamy, white to gray, mucoid fluid. Histologic lesions in the air sacs and bronchi were epithelial hyperplasia, discharge of mucocellular exudate to the mucosal surface, thickening of the mucosa by cellular infiltrates, loss of cilia, and dilation of mucous glands. Weight gains for IT-inoculated birds were lower (P less than .05) than controls from 14 to 21 DAI, although weight gains for the 5-week period were not significantly different.(ABSTRACT TRUNCATED AT 250 WORDS)

Cryptosporidium Pathogenicity and Virulence

“…C. parvum is now regarded as an economically important cause of neonatal diarrhea in calves and lambs (33)(34)(35)(36)(37)(38)(39). Another species, Cryptosporidium baileyi, is recognized as an important cause of respiratory disease in poultry and game birds (40)(41)(42)(43).…”

Cryptosporidiosis in birds ‐ A review

“…The body weight gains of inoculated broiler chicks were lower than those of sham-inoculated controls (Ley, 1987); gross or microscopical lesions were not reported. In other studies, peroral inoculation of chickens and turkeys with oocysts of C. baileyi isolated from chickens resulted in parasitisation of epithelial cells of the bursa of Fabricius, ileum, large intestine and trachea Blagburn et al, 1987;Lindsay et al, 1987a, b, c). Other parts of small intestine were not infected and the birds were clinically normal.…”

Effect of Cryptosporidium baileyi in specific pathogen free chickens vaccinated (CVI988/Rispens) and challenged with HPRS-16 strain of Marek's

“…The respiratory symptoms noted in the R0C4M15 group were certainly due to Cryptosporidium infection because the six chickens that died from days 17 to 39 during the respiratory disease showed massive infection of the respiratory tract by the parasite (Table 2 and Figure 2). C. baileyi inoculated alone by intratracheal or intraperitoneal route is able to induce respiratory disease and even mortality (Blagburn et al, 1987;Lindsay et al, 1987b;Lindsay & Blagburn, 1990), proving the primary respiratory disease potential of C. baileyi in the absence of other demonstrable pathogens (Blagburn et al, 1991). Respiratory disease following intratracheal inoculation at day 4 of C. baileyi oocysts in B13 chickens induced 20% mortality (data not shown).…”

“…A decrease in humoral response to antigens such as sheep red blood cells and Brucella abortus (Rhee et al, 1998b,c), and in cell-mediated immunity, measured with the delayed hypersensitivity index (Blagburn et al, 1987), has also been induced by C. baileyi infections. It has therefore been suggested that attention should be given to the ability of C. baileyi-infected birds to respond to other agents such as viruses and intracellular bacteria.…”

“…in poultry and the most commonly associated with disease in chickens. It may infect the respiratory tract, bursa of Fabricius and cloaca of chickens Blagburn et al, 1987), turkeys (Lindsay et al, 1987a) and ducks (Lindsay et al, 1989). Under experimental conditions, respiratory cryptosporidiosis occurs when birds are inoculated intratracheally or intra-abdominall y (Lindsay et al, , 1987b.…”