Mycoplasma bovis-associated pneumonia and arthritis complicated with pyogranulomatous tenosynovitis in calves.

Immunohistochemistry and bacteriologic culturing were used to detect Mycoplasma bovis in tissue specimens from feedlot calves affected with pneumonia and arthritis. Two herds with 110 Charolais calves and 25 Angus calves were examined. Clinical signs included severe respiratory distress, anorexia, pyrexia, and lameness, which affected nearly a third of the calves. Lung lesions were characterized by numerous abscesses. Synovial lesions of the limbs included pyogranulomatous tenosynovitis, bursitis, and synovitis, particularly in the areas of the carpal and elbow joints. Abscesses in lung and synovial tissues contained accumulations of M bovis antigens, as revealed by immunohistochemistry. The findings of this report indicate that infection with M bovis may result in a pneumonia-arthritis syndrome with pyogranulomatous lesions in calves.

Immune responses to the capsular polysaccharide of Mycoplasma dispar in calves and mice.

Humoral and cell-mediated immune responses to the capsular polysaccharide (CPS) of M. dispar and polygalacturonic acid (pGaIU--a structurally similar polysaccharide) were investigated in calves experimentally infected with Mycoplasma dispar and in mice immunized with CPS or pGaIU. Sera, tracheobronchial lavage and nasal fluids, collected before and after infection in calves, were checked for the presence of anti-CPS and anti-pGaIU antibodies. The sera from mice injected with CPS or pGaIU were checked for different classes of anti-CPS and anti-pGaIU antibodies. Peripheral blood lymphocytes from calves and splenic lymphocytes from mice were monitored for specific proliferative responses to CPS and pGaIU. At about 2 weeks post-infection, anti-CPS IgM response in serum, anti-CPS and anti-pGaIU IgM and IgA response in lavage fluid and lymphocyte proliferative response was seen in the calves. Mice immunized with CPS and pGaIU gave exclusively IgM responses. No secondary response was seen in mice immunized with CPS in contrast to mice immunized with pGaIU. Antibodies cross-reactive with pGaIU were present in the sera of CPS-immunized mice but antibodies cross-reactive with CPS were not found in pGaIU-immunized mice. No significant blastogenic response was shown by mouse splenocytes to CPS or pGaIU.

Immunohistochemical and pathological study of Mycoplasma bovis-associated lung abscesses in calves.

Out of 45 cases of fatal chronic pneumonia in calves examined for Mycoplasma bovis infection from February to July 1994, 11 cases with pulmonary abscesses that were culture positive for M. bovis were encountered. The cases were studied in detail using a recently developed monoclonal antibody-based immunoperoxidase technique. Mycoplasma bovis organisms were detected in specific locations at all stages of abscessation observed. In bronchioles or terminal airways within which abscesses developed, M. bovis was located at the epithelial surface and in close association with infiltrating neutrophils and macrophages. Abscessed airways that had lost the epithelium were encapsulated and were seen as coagulative necrotic foci that stained intensely for M. bovis, especially at the periphery. Some foci stained weakly and such might have been resolving lesions. Mycoplasma bovis was also demonstrated at sites of mild mononuclear cell infiltration in the livers and kidneys of 2 calves. The mycoplasma was detected within bile ducts in the liver and in the tubular epithelium of the kidney. Abscesses not staining for M. bovis, presumably caused by other pathogens, were seen concurrently with M. bovis-associated abscesses in some lungs. Thirteen other M. bovis-positive cases showed no abscesses, possibly indicating heterogeneity among M. bovis strains. Three other cases with abscesses were negative for M. bovis by culture and immunoperoxidase staining. The monoclonal antibody-based immunohistochemical technique is efficient for specific detection of M. bovis in cases of enzootic pneumonia of calves with or without abscessation. Mycoplasma bovis is implicated in the pathogenesis of lung abscesses in some calves.

Identification and control of the cis-acting elements of the immediate early gene of equid herpesvirus type 1.

Consensus cis-acting DNA sequences upstream of the immediate early (IE) gene of equid herpesvirus type 1 (EHV-1, strain Ab4) were identified. One copy of the conserved motif TAATGARATTC, which is the binding site for the host cellular factor Oct-1 and herpes simplex virus type 1 (HSV-1) virion protein, VmW65, complex, was identified at positions -630 to -620. Using transient transfections and chloramphenicol acetyltransferase assays the IE promoter of EHV-1 was shown to be trans-activated by VmW65 within the region -685 to +73. Ultraviolet light-inactivated EHV-1 was able to stimulate the expression of the IE gene of EHV-1 as well as HSV-1, indicating that EHV-1 possesses a protein equivalent to VmW65. The ubiquitous equid herpesvirus type 2 (EHV-2), which is not known to be a primary pathogen, was also able to trans-activate the EHV-1 and HSV-1 IE genes. Further work is being performed in order to identify the nature of the EHV-1 and EHV-2 trans-activating proteins.

The choice of adjuvants in Mycoplasma vaccines.

The use of adjuvants in vaccine production is an important aspect of potent vaccines. This investigation was concerned with finding the most efficient adjuvants for use in Mycoplasma vaccines produced in Nigeria. Four different vaccines were produced from the Gladysdale strain of Mycoplasma mycoides subspecies mycoides. They differed depending on the type of adjuvants used. Each vaccine was used to vaccinate eight cattle using a dose of 1 ml. Two other groups of eight cattle were used as controls. One of the two groups received 1 ml dose of inactivated Gladysdale vaccine without adjuvant while the second group received 1 ml dose of saline. The number of cattle that had the peak complement fixing (CF) antibody titres of 1/80 in each group of cattle was four for vaccine containing aluminium hydroxide gel, eight for vaccine containing liquid paraffin, one for vaccine containing sodium alginate and one for vaccine without adjuvant. Seven cattle from the group vaccinated with vaccine containing Freund's incomplete adjuvant had peak CF antibody titres of 1/80 or higher. The two groups vaccinated with vaccine containing liquid paraffin and Freund's incomplete adjuvant survived challenge at 6 months post vaccination. Freund's incomplete adjuvant and liquid paraffin containing 10% Arlacel A are the most efficient adjuvants.

Frequency of involvement of pox virions in lesions of bovine dermatophilosis.

By combined electron microscopical and serological methods the rate of involvement of pox virions within lesions of bovine natural dermatophilosis was determined. Scabby lesions of 40 (77%) out of a total of 52 cases were positive for the virions, while sera of all infected animals which reacted positively for pox viral antibodies (LSD) was significantly higher (P less than 0.001) in comparison to those of healthy-appearing animals. The virions in all cases had a uniform oval to cylindrical morphology with a mean measurement of 110 X 280 nm. A synergistic interplay involving the initiation of the scabby lesions by the virions and their subsequent trapping within keratin deposits, followed by their release through the keratolytic activity of Dermatophilus congolensis appear to have obtained in cases.

Microbiology of the genitalia of nulliparous and postpartum Savanna brown goats.

A study of the bacterial flora of the genitalia of nulliparous Savanna Brown does was carried out both before breeding and at different intervals postpartum to investigate the type of microbial organisms that could be present in the uterus, cervix and the vagina respectively. Of 29 pre-breeding vaginal swabs, Staphylococcus sp. was isolated from 20 goats, Streptococcus sp. from 15 goats and Micrococcus sp. from four goats. Mycoplasma agalactiae was isolated from five goats. The postpartum vagina did not show any appreciable change in the microbial flora, except that Escherichia coli was encountered in two cases. The uterus yielded E. coli from the goats slaughtered 2 days postpartum; Micrococcus sp. from goats slaughtered 12 days postpartum; Staph. aureus from goats slaughtered 16 days postpartum and Staph. aureus from goats slaughtered 24 days postpartum. Also in these two cases-a goat slaughtered at two days postpartum (dpp) and a goat slaughtered 16 dpp-E. coli was present in the uterus. Other isolates from the uteri of slaughtered goats were Micrococcus sp. (12 dpp), Staph. aureus and Micrococcus sp. (16 dpp) and Staph. aureus (24 dpp).

Immunodepressive effects of trypanosomal infection in cattle immunized against contagious bovine pleuropneumonia.

Groups of cattle infected singly with Trypanosoma vivax and T. congolense and, with a combination of T. vivax and T. congolense, were vaccinated against contagious bovine pleuropneumonia (CBPP) 6 weeks before or after infection. All animals were revaccinated 12 weeks after primary vaccination. The primary antibody responses in cattle vaccinated 6 weeks after infection with T. vivax and a combination of T. vivax plus T. congolense were slightly depressed in contrast to other groups which were similar in their response to the control group. Although secondary antibody responses developed in all infected groups, with a delay in those infected with T. congolense, they did not reach the levels of the controls. In spite of the slight depression in antibody responses, however, 50% of the vaccinated trypanosomal animals contracted CBPP on exposure to experimental infection while the vaccinated controls were immune. It is suggested that the protective immunity to CBPP engendered by vaccination is impaired during infection with African trypanosomes and that the level of antibody response to CBPP vaccination in trypanosomal animals does not reflect the degree of immunodepression. The importance of trypanosomiasis control in ensuring success of vaccination campaigns against CBPP is discussed.

Experience in northern Nigeria with countercurrent immunoelectrophoresis, double diffusion and indirect haemagglutination tests for diagnosis of hydatid cyst in camels.

Sera from 36 slaughtered camels with proven hydatid disease, from 46 camels found to be free of hydatidosis at post-mortem meat inspection, and from 26 animals with confirmed caprine heartwater, bovine trypanosomiasis and cysticercosis were examined. The indirect haemagglutination was found to be the most sensitive but least specific of the three tests. Ouchterlony's double diffusion (DD) test was specific and fairly sensitive. Although the countercurrent immunoelectrophoresis was as specific as DD, it was the least sensitive of the three serological tests. All three serological tests were always positive in camels with hydatid cyst infection affecting both the liver and the lung. A combination of indirect haemagglutination and Ouchterlony's double diffusion test could be useful for diagnosing hydatidosis in camels and probably other animals.

Experimental transmission of Echinococcus granulosus of "camel-dog" origin to goats, sheep, cattle and donkeys.

The infectivity of a camel strain of Echinococcus granulosus experimentally raised in dogs for domesticated food and burden animals was investigated. Of the animal species that were inoculated orally with gravid segments, hydatid cysts developed poorly in goats and sheep, less well in cattle and not at all in donkeys by six month post-inoculation. Cysts were most frequently found in the lungs, although other organs such as liver and spleen also contained cysts. Histological examination of affected organs in these animals revealed the cysts surrounded by a granulomatous cellular reaction. Protoscolices and brood capsules were lacking at the time of examination. Thus it appears that although hydatid cysts could develop in some of these animal species within six months, the cysts were immature.

Mycoplasma pneumoniae and the aetiology of lobar pneumonia in northern Nigeria.

Over a six-month period we studied 74 adult Nigerians who presented consecutively to Ahmadu Bello University Teaching Hospital, Zaria, with lobar or segmental pneumonia. Pneumococcal infection was diagnosed in 50% by the detection of pneumococcal polysaccharide antigen in serum or purulent sputum: 24% had pneumococcal antigenaemia. Twelve patients had evidence of Mycoplasma pneumoniae infection and half of these also had pneumococcal infection. The suggestion that M pneumoniae respiratory infection may predispose to serious bacterial pneumonia is discussed. The initial clinical and radiological features were similar in the pneumococcal and M pneumoniae groups. Raised cold agglutinin titres were not a reliable indication of M pneumoniae infection, perhaps due to altered autoantibody production in Nigerians. Pneumonia was commoner in the dry season, probably related to depressed nasopharyngeal defences caused by drying. Less common causes of lobar pneumonia that were found are also discussed and no cases of legionnaires' disease were identified.

The epidemiology of echinococcus infection in Kaduna State, Nigeria.

Infection of dogs with Echinococcus gramulosus is recorded for the first time in Kaduna State. Observations on 330 dogs from different suburbs revealed an incidence of 1.2 per cent. Of slaughtered stock examined, hydatid cyst infections were found in sheep (7.1 per cent), goats (18.4 per cent), cattle (1.5 per cent), camels (70.9 per cent) and pigs (5 per cent).

A survey of gastro intestinal helminth parasites of stray dogs in Zaria, Nigeria.

A survey of helminth parasites in stray dogs was carried out in the Zaria area. Out of 180 dogs examined 65.6 per cent (118/180) were found positive for Ancylostoma caninum, while Toxocara canis and Trichuris vulpis were detected in 41.1 per cent (74/180) and 13.9 per cent (25/180) respectively. Other helminth parasites found Taenia ovis 35 per cent (63/180) Taenia hydatigena 67.8 per cent (122/180), Echinococcus granulosus 0.006 per cent (1/180) and Dipylidium caninum 97.8 per cent (176/180).