Capsular serogroups of Pasteurella multocida isolated from animals in Zimbabwe.

Pasteurella multocida is isolated from a variety of disease conditions from different animal species in our diagnostic laboratory. In order to determine serogroup distribution among the isolates, an indirect haemagglutination test using glutaraldehyde-fixed sheep red blood cells was employed. A serological examination of 79 isolates revealed that 47/79 were of capsular serogroup A, 11/79 capsular serogroup D, 4/79 capsular serogroup B and 17/79 were untypable strains. None of the isolates belonged to either serogroup E or F. All those from cases of classical pasteurellosis could be grouped, but a significantly high proportion of those which originated from companion animals were untypable. The significance of these results is discussed. This report appears to be the first detailed information on the prevalence of various serogroups of P. multocida in animals in southern Africa.

Phenotype and serotype of Pasteurella multocida isolates from diseases of dogs and cats in Zimbabwe.

A variety of disease manifestations, comprising skin bite wounds, pyothorax, respiratory and genitourinary tract infections, in 202 dogs and cats presented to the University Clinic, were investigated for the presence of Pasteurella multocida. Of these, 25-42% of various cases (69) were found to be infected with P. multocida. P. multocida-associated respiratory tract infections were more common than bite wounds or genitourinary tract infections. The regimen of treatment consisted of those antibiotics, sensitivity to which had been confirmed in vitro. Following detailed characterization of the isolates of P. multocida, in order to assign them to the reclassified taxa of Pasteurella, a preponderance of P. multocida subspecies multocida and septica were recorded. There did not appear to be a correlation between the reclassified taxa and their serotypes. Certain strains of different species or subspecies belonged to a common serotype and vice versa. However, the strains which were serotyped belonged to capsular type A, except for a solitary isolate from a cat which was capsular type D. Type D is known to cause atrophic rhinitis and does not appear to have been isolated either from a dog or a cat. Two strains, one from a dog and another from a cat, were identified as group EF-4 bacteria. This group of organisms has been incriminated in human wounds resulting from dog/cat bites, and has so far not been reported in Africa. Three different species, P. stomatis, P. dagmatis and P. multocida subspecies multocida were simultaneously isolated from a case of chronic bronchitis in a dog. There was no evidence of any relationship between disease manifestation in a host and the isolation of a particular taxon of Pasteurella, except that P. canis and Pasteurella taxon 16 were only isolated from dogs.

Strains of Actinobacillus spp. from diseases of animals and ostriches in Zimbabwe.

Among the Actinobacillus spp. only A. lignieresii represents a homogenous and well studied taxon. However, haemolytic and non-haemolytic strains of A. equuli and A. suis are also isolated from a wide range of diseases in a variety of hosts. These isolates often pose problems in definitive identification. Consequently, several studies have been published, emphasizing the need for detailed studies to reclassify various members of this genus and also to assess their disease significance. We isolated 48 strains of Actinobacillus from clinical cases in horses, cattle, sheep, cat, pigs and ostrich. In order to investigate the association of various taxa of Actinobacillus in different pathological conditions in these hosts, the Zimbabwean isolates were characterized in detail and assigned to the recently described taxa of Actinobacillus. Representative strains of different taxa were also confirmed at the Department of Veterinary Microbiology, Frederiksburg C, Denmark. Of the 48 isolates, 22 were identified as A. lignieresii, 13 as A. equuli; 6 as A. suis, four as belonging to Taxon 11 and one as belonging to Taxon 9. These two taxa were recently described. Details of pathological conditions in the respective hosts and the significance of isolation, are discussed. We have reported for the first time isolation of A. lignieresii from a post-operative wound in a cat and there is also a first report of isolation from an ostrich. We considered A. equuli to be the primary cause of equine abortion and septicaemia, and Taxon 9 as causing "sleepy foal" disease. We did not encounter any case of "wooden tongue", but isolated A. lignieresii from cases of superficial lymphadenitis in cattle and sheep. This appears to be a first report of detailed descriptions of Zimbabwean strains of Actinobacillus spp.

Brucellosis surveillance and control in Zimbabwe: bacteriological and serological investigation in dairy herds.

Brucellosis in dairy cattle is endemic in Zimbabwe. The prevalence continues to be monitored intensively. Only milk and serum samples are routinely screened. Attempts to culture Brucella spp. from clinical specimens are seldom made. Consequently, incidence of various Brucella spp. within Zimbabwe is virtually unknown, despite the high serepositivity reported. This information is paramount in understanding the transmission cycle and is also significant to public health; particularly as B melitensis infects humans more often than do the other brucellae. This paper describes the results of bacteriological and serological investigations of brucellosis in a dairy from near Bulawayo. The said farm was selected for the present pilot study because of the high incidence of reported abortion. The milk ring test was employed to test the bulk pooled milk samples once a month for 14 months. The test was recorded highly positive on all 14 occasions. To locate reactors, milk samples from 36 individual cows were similarly tested. Of these, 21 (almost 59%) were found to be reacting positively. One hundred and seventy-seven animals were marked for serotesting. Of these 40 (approximately 25%) showed quite high serum titres (> 1:360) in both the STT and the Rosebengal test. The farmer was advised to havet all abortions full investigated. However, all the clinical material from cases of abortion, except one, were received in an advanced state of putrefaction. From this, Brucella was isolated on culture from stomach contents and cotyledons. The isolates from both the sites were characterized in detail, employing dye inhibition, phagetyping; the oxidative metabolic test and agglutination with monospecific sera. Both the isolates belonged to B. abortus biovar I, which was confirmed by the Central Veterinary Research Laboratory, Weybridge. The significance of isolation and the need to intensify similar studies have been discussed.

Mycoplasma-associated polyarthritis in farmed crocodiles (Crocodylus niloticus) in Zimbabwe.

Outbreaks of polyarthritis in farmed crocodiles (Crocodylus niloticus) on five farms in Zimbabwe are described. Cases were reported only among the rearing stock aged 1-3 years. No breeding stock suffered. Morbidity was about 10% and the mortality even lower. All the sick animals consistently displayed swollen limb joints as well as progressive lameness and paresis. The synovial structures in subacute cases contained mycoplasmas and excess turbid mucus which, at a later stage of the disease, became yellowish, inspissated and sterile. Cellular changes in the joint capsule included oedema, necrosis of the superficial layers of membrane, lymphocytic infiltration and fibrosis. Evidence of pneumonia was observed only at necropsies. Fifteen isolates of Mycoplasma were cultured from the clinical specimens collected from the four sick and three dead crocodiles. The affected joints of all these animals yielded Mycoplasma in pure culture, but the culture from lungs yielded post-mortem invaders also. The sick animals were treated with a single intramuscular injection of long-acting tetracycline (10 mg/kg), and oxytetracycline mixed in feed at 550 mg/kg was fed for 10 d. The treatment appeared to be effective in ameliorating the clinical signs, but in some cases inflammatory swelling persisted. All 15 the isolates conformed to the characteristics of the genus Mycoplasma, and were serologically indistinguishable in growth-inhibition (Gl) tests. Although these isolates shared the main biochemical characteristics of Mycoplasma capricolum, they differed serologically. Also goats were refractory to experimental infection with crocodile strains. In crocodile yearlings, however, the disease was reproduced with an isolate from one of the affected farms. The source of infection remained elusive.(ABSTRACT TRUNCATED AT 250 WORDS)

Phenotypic characterization of Zimbabwean isolates of Pasteurella multocida.

The phenotypic characteristics of 60 Zimbabwean isolates of Pasteurella multocida sensu stricto, from disease syndromes in different host species were studied. A number of representative strains were also serotyped. Consistent results were obtained in the tests for; catalase, oxidase, urease, indole, acid in glucose, inositol, salicin and sucrose. There was no obvious relationship between serotype, host or disease and the pattern of utilization of certain substrates by an isolate. This has been discussed in the context of recent proposals to reclassify Pasteurella and P. multocida on genotypic and phenotypic studies. It is suggested that notwithstanding the relevance of genetic studies in circumscribing P. multocida, the phenotype and disease significance of the taxon should not be ignored. A case of bronchitis in a dog which was simultaneously colonized by three different strains of Pasteurella is described. Also septicaemic pasteurellosis in a Nile crocodile (Crocodylus niloticus) is reported and for the first time prevalence of various serotypes in pasteurellosis of animals in Zimbabwe.

Concurrent systemic cryptococcosis and haemangiosarcoma in a dog.

A young dog with progressive neurological signs was humanely killed by the injection of barbiturate for postmortem examination. Lesions in the nose, lung, pancreas, lymph nodes, kidneys and the meninges were heavily infiltrated with Cryptococcus neoformans. In addition, haemangiosarcoma was detected in the right atrium. The finding of systemic mycosis and neoplasia together in a young dog suggests an immunosuppressed state.