Prevalence of Mycoplasma and Chlamydia in the nasal flora of dairy calves.

Nasal swabs from dairy calves in 20 selected herds were collected once in each of three sampling periods in one year and cultured for mycoplasmas and chlamydiae. Seventy-seven of 411 calves (19%) and 16 of 20 herds (80%) were positive for mycoplasmas at least once throughout the year, and all of 378 calves sampled from the 20 herds were negative for chlamydiae. Thirty-one percent of the isolates were Mycoplasma bovirhinis; other species isolated less frequently were Mycoplasma bovis, Mycoplasma arginini, and Acholeplasma laidlawaii. There was no evidence of respiratory tract disease at the time of sampling in calves studied.

Evaluation of secondary enrichment for detecting Salmonellae in bobwhite quail.

Secondary enrichment of cultures in tetrathionate-brilliant-green broth substantially increased Salmonella recovery over that achieved with primary tetrathionate-brilliant-green broth or primary selenite-cystine broth.

A modified technique for assaying avian immunoglobulin-M-secreting cells.

A localized complement-dependent hemolytic assay in modified Cunningham chambers for enumerating avian immunoglobulin-M (IgM)-secreting spleen cells is defined. The maximum number of IgM-secreting spleen cells was present six days after sheep red blood cells (SRBCs) were injected. Intra-abdominal injection of SRBCs resulted in greater but more variable numbers of IgM-secreting cells at the time of maximum response than did either intramuscular or intravenous injection. Fresh chicken serum (FCS) with 10% guinea pig serum was an equally or more effective source of complement for the assay than was FCS alone.

Effect of reovirus infection and dietary levels of selected vitamins on immunocompetence of chickens.

The immunocompetence of 8-week-old reovirus WVU 2937-infected and uninfected chickens fed various dietary levels of biotin, niacin, choline, or folic acid was evaluated in four experiments. Antibody production to sheep red blood cells (SRBC), wattle responses to phytohemagglutinin-P (PHA-P), and wattle responses of tuberculin-sensitized chickens to bovine-purified protein derivative (PPD) were examined in five chickens per treatment. Dietary deficiencies had no effect on the in vivo T-cell immune responses to PPD, PHA-P, or humoral hemagglutinating-antibody production to SRBC. Reovirus-infected and uninfected chickens fed biotin at double the National Research Council (1977) requirement demonstrated decreased PPD responses. Lower hemagglutinating-antibody titers in the uninfected chickens and increased titers in the infected chickens were observed in those fed 200% of the requirement of biotin when compared with the chickens fed 20% and 100% biotin diets. Reovirus infection had no effect on PPD and PHA-P responses. However, in the choline experiment, reovirus-infected chickens had elevated titers. These data indicate that reovirus infection had no adverse effect on the immunocompetence of chickens 8 weeks postinfection. Dietary deficiencies also had no adverse effect on the immunocompetence of 8-week-old reovirus-infected and uninfected chickens.

A comparison of avian and mammalian cell cultures for the propagation of avian reovirus WVU 2937.

Two avian and seven mammalian cell lines were evaluated for their application in propagating avian reovirus WVU 2937. Cultures were compared for monolayer-formation time, support of viral replication, passages and postinfection time required for expression of cytopathic effect (CPE), type of CPE, and virus yield. CPE was observed on the first passage with infected egg yolk in primary chicken embryo kidney cells, primary through tertiary chicken embryo liver (CEL) cells, and African green monkey kidney (VERO) cells; on the third blind passage of infected supernatant in Georgia bovine kidney cells, Crandall feline kidney cells, and baby hamster cells; on the fifth blind passage in rabbit kidney cells; and on the tenth blind passage in porcine kidney cells. CPE was not observed after 10 viral passages in rabbit bone-marrow cells. Monolayer formation time and postinfection time for CPE expression occurred sooner, and virus yield was greater, with CEL and VERO cells than with other cell lines.

Enhanced incidence of leg abnormalities in reovirus WVU 2937-infected chickens fed various dietary levels of selected vitamins.

Five experiments were conducted to evaluate the incidence of leg abnormalities of 4-, 6-, and 8-week-old reovirus WVU 2937-infected and uninfected chickens fed diets containing 20%, 100%, or 200% of the 1977 National Research Council nutrient requirements (NRC-77) of poultry for manganese, biotin, niacin, choline, or folic acid. Reovirus infection significantly elevated the incidence of leg abnormalities in the biotin-, niacin-, and folic-acid-deficient chickens and decreased the incidence of leg abnormalities in choline-deficient chickens. Reovirus-infected male chickens had a significantly greater incidence of leg abnormalities than reovirus-infected female chickens in the biotin, niacin, and folic acid studies. No sex differences in the incidence of leg abnormalities were observed in uninfected chickens. The incidence of leg abnormalities decreased with increasing dietary levels of biotin, niacin, choline, or folic acid in all chickens except reovirus-infected male chickens in the biotin study. In the manganese study, neither reovirus infection nor dietary level had any effect on the incidence of leg abnormalities in male or female chickens.

Responses of specific-pathogen-free chicks to concomitant infections of reovirus (WVU-2937) and infectious bursal disease virus.

Specific-pathogen-free white leghorn chicks concomitantly infected with both infectious bursal disease virus (IBDV) and reovirus (WVU-2937) on day 1 had significantly lower (P less than 0.05) virus-neutralizing- and precipitating-antibody geometric mean titers (GMT) to reovirus than chicks infected with only reovirus on day 1 but had a similar incidence of inflammation of the metatarsal digital flexor tendons. Chicks infected with IBDV on day 7 and reovirus on day 14 had a greater incidence of inflammation of the tarsometatarsal digital flexor tendons and lower neutralizing- and precipitating-antibody GMT to reovirus than chicks infected with only reovirus on day 14. Chicks infected with both viruses on day 1 had a significantly lower (P less than 0.05) neutralizing-antibody GMT to IBDV than chicks infected with only IBDV.

Severity of tenosynovitis in reovirus-infected chickens fed various dietary levels of choline, folic acid, manganese, biotin, or niacin.

Five experiments were conducted to determine the incidence and severity of tenosynovitis in tendons distal to the tarsal joint in 4-, 6-, and 8-week-old reovirus WVU 2937-infected chickens fed diets containing 20%, 100%, or 200% of the 1977 National Research Council nutrient requirements (NCR-77) of manganese, biotin, niacin, choline, or folic acid. Male chickens, but not female chickens, fed 20% or 100% or the NRC-77 level of folic acid had consistently higher lesion scores of tenosynovitis than male chickens fed the 200% NRC-77 level of folic acid. Increasing dietary manganese levels from 20% to 200% NRC-77 reduced the severity of tendon swelling in 6- and 8-week-old male chickens and appeared to increase the severity of tendon swelling in 8-week-old female chickens. Male chickens fed 20% of the NRC-77 required level of biotin had numerically more severe tenosynovitis at 6 weeks of age and significantly more severe tenosynovitis at 8 weeks of age than male chickens fed 100% and 200% of the NRC-77 level of biotin. Increasing dietary choline levels from 20% to 200% of the NCR-77 required level increased the severity of tenosynovitis numerically at 6 weeks of age and significantly at 8 weeks of age. When data were pooled across diet, male chickens had significantly more severe tenosynovitis than female chickens at 4, 6, and 8 weeks of age in the choline experiment and at 4 and 6 weeks of age in the folic acid experiment. Differences in the severity of tenosynovitis of individual treatment means (sex X diet X infection interaction means) occurred at only the 20% or 100% NRC-77 level of choline or folic acid. Male chickens also had more severe tenosynovitis than female chickens when fed 20% of the NRC-77 required level of manganese for 6 or 8 weeks.

Sequential mitogen stimulation of peripheral blood lymphocytes from chickens inoculated with infectious bursal disease virus.

Chickens were inoculated wih the pathogenic Edgar strain of infectious bursal disease virus at 1 week, 2 weeks, or 1 day of age. In the 3 experiments, phytohemagglutinin stimulation of peripheral blood lymphocytes was significantly decreased on day 3 or 4 after inoculation. Subsequently, on days 7 through 21, stimulations were similar between lymphocytes from inoculated birds and those from control birds. Pokeweed mitogen stimulation was affected minimally in virus-inoculated chickens. In each experiment, on day 7, the spontaneous [3H]thymidine uptake was greater in nonstimulated lymphocyte cultures from inoculated chickens than in such cultures from control chickens. In an additional experiment, chickens 1 week of age were exposed to a pathogenic vaccinal virus given in their water. The vaccinal virus exposure resulted in significant decrease of phytohemagglutinin stimulation of lymphocytes on days 3 and 7 of the experiment. A significant decrease in pokeweed mitogen stimulation was observed on day 10 after inoculation.

Frequency and duration of paratyphoid organism shedding by experimentally infected bobwhite quail (Colinus virginianus).

Four-week old bobwhite quail (Colinus virginianus) were experimentally infected with Salmonella urbana, S. infantis, S. newport, S. gaminara, S. braenderup, and S. litchfield. Rates of mortality varied from 0 to 50%. The rate of shedding of paratyphoid organisms varied from 14 to 100% for 18 or more days after infection. The maximum duration of shedding was 53 days by 12% of the quail infected with S. braenderup and the minimum duration was 18 days by 14% of the quail infected with S. litchfield.

Effect of subcutaneous pox vaccination of young chicks on immune responses and weight gains.

Two fowl pox and two pigeon pox vaccines were administered subcutaneously in the dorsum of the neck of specific-pathogen-free (SPAFAS) chicks at day of hatch in separate studies. Treatment levels used were 1:2, 1:10, or 1:50 dilution of the recommended wing web dose. Both pigeon pox vaccines and one fowl pox vaccine depressed body weight gains significantly by day 14. Mean body weight gains of female chicks were less affected by pigeon pox vaccines than by fowl pox vaccines. The mean hemagglutination-inhibition (HI) antibody titer to Newcastle disease virus (NDV) of chicks given one pigeon pox vaccine at the 1:2 dilution was significantly lower (P less than .01) than titers of sham-treated controls. The number of immunoglobulin-M (IgM) secreting cells in the spleen was significantly less (P less than .05) at day 14 in all pox vaccinated chicks when compared to sham-treated controls.

Infectious bronchitis and mixed infections of Mycoplasma synoviae and Escherichia coli in gnotobiotic chickens. I. Synergistic role in the airsacculitis syndrome.

The synergistic role of infectious bronchitis virus (IBV) and mixed infections of Mycoplasma synoviae (MS) and Escherichia coli (EC) in the airsacculitis syndrome was evaluated in gnotobiotic chickens. Relative air sac lesion score indexes, in descending order of severity, from various combinations of organisms were: 9.5-IBV, MS, EC; 6.8-IBV, EC; 4.5-IBV, MS; 2.7-IBV; and 0.5-MS, EC. Infectious bronchitis virus caused a mild fibrinous inflammation. M. synoviae combined with IBV increased heterophilic and follicular lymphoid infiltration and mortality. E. coli combined with IBV increased exudation and prolonged airsacculitis. Concentrations of fibrinogen, gamma globulin, and total plasma proteins were elevated significantly by combined infections of IBV, MS, and EC (P < 0.01).