Cryptosporidium parvum infection in bovine neonates: dynamic clinical, parasitic and immunologic patterns.
Twenty-six experimentally infected calves were monitored daily for oocyst excretion. All began excreting oocysts 3-6 days p.i. Most calves (n = 23) excreted oocysts for 6-9 days, with a daily range from 4 x 10(2) to 4.15 x 10(7) oocysts g(-1) of faeces. Over half the calves excreted peak numbers of oocysts 6-8 days p.i. Diarrhoea, observed intermittently beginning as early as day 3 p.i., lasted 4-16 days and varied greatly in severity from calf to calf. In a second study, nine of 18 calves were orally inoculated with 5 x 10(6) oocysts between birth and 2 days of age and nine remained uninfected. Monoclonal antibodies for cell surface markers indicated substantial increases in CD4+ and CD8+ T cells in the intraepithelial lymphocyte population of the ilea of infected calves at 7-9 days of age. RT-PCR demonstrated increases in mRNA for interleukin-12 and interferon-gamma that correlated with increases in both CD4+ and CD8 + intraepithelial lymphocyte cells. Increased mRNA for interleukin-12 and interferon-gamma from lamina propria lymphocytes correlated with increased numbers of CD8+ cells. No changes were found in interleukin-2, interleukin-4 or interleukin-10 mRNA levels. However, interleukin-15 mRNA, possibly from epithelial cells contaminating intraepithelial lymphocytes, was decreased in infected calves and had a negative correlation with increases in CD4+ and CD8+ cells. No differences were detected in mRNA levels for cytokines from lymph node lymphocytes.
Fayer
R
R
United States Department of Agriculture, Agricultural Research Service, Immunology and Disease Resistance Laboratory, Beltsville, MD 20705, USA. rfayer@ggpl.arsusda.gov
Gasbarre
L
L
Pasquali
P
P
Canals
A
A
Almeria
S
S
Zarlenga
D
D
D000818:Animals; D000831:Animals, Newborn; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D002417:Cattle; D002418:Cattle Diseases; D003457:Cryptosporidiosis / Q000276:immunology / Q000503:physiopathology / Q000662:veterinary*; D016785:Cryptosporidium parvum / Q000302:isolation & purification; D003967:Diarrhea / Q000469:parasitology / Q000662:veterinary; D005243:Feces / Q000469:parasitology; D007111:Immunity, Cellular; D007371:Interferon-gamma / Q000096:biosynthesis; D018664:Interleukin-12 / Q000096:biosynthesis; D018655:Lymphocyte Count; D008297:Male; D012333:RNA, Messenger / Q000096:biosynthesis; D014158:Transcription, Genetic
D012333:RNA, Messenger; D018664:Interleukin-12; D007371:Interferon-gamma