Borrelia theileri infection

G C BISHOP*

GENERAL INTRODUCTION: SPIROCHAETES

Introduction

According to Canham,⁸ Borrelia theileri was first found in 1902 in the blood of cattle, sheep and a horse in South Africa by Theiler, and causes a benign disease with a very low mortality.⁴ Borreliosis has been reported from many countries in Africa,^{1, 12, 16, 21, 22, 27} South America,¹⁰ and Europe,¹¹ and from Australia,⁷ Mauritius³ and Madagascar.²⁶ The disease, although fairly widespread and common,^{12, 21} is of little economic importance and few deaths have been reported.

Aetiology and epidemiology

Borrelia theileri (synonyms Treponema theileri, Spirochaeta theileri) varies somewhat in length, being slightly shorter in solipeds than in cattle, sheep, goats and antelope.⁷ Most reports give its width as 0,25 to 0,30 µm and its length as 9 to 18 µm,⁷ but some maintain that most are 20 to 30 µm long.⁶ Although the organism appears shorter in solipeds, transmission from equids to cattle has been successful.¹²

Figure 133.1  Blood smear: Borrelia theileri

Borrelia spp. are difficult to culture and specific media such as Barbour-Stoener-Kelly are required for this purpose.¹⁷ There are no reports that B. theileri has ever been cultured in vitro: it has only been propagated in vivo in splenectomized calves.

Several tick species have been listed as vectors of B. theileri, including Rhipicephalus evertsi evertsi, Boophilus decoloratus, B. australis, B. microplus and B. annulatus. ^{2, 6, 7, 21, 22, 24, 25} The nymphal and adult stages of these ticks are more infective than the larvae and the parasite is passed from the parents via the eggs to their progeny.²⁴ Infection by B. theileri is often associated with infection by Babesia spp., which has led some workers to believe that B. theileri may be of secondary importance.^{12, 27}

Pathogenesis and clinical signs

Following a prepatent period of two to three weeks,^{7, 20, 23} spirochaetes are usually found in the peripheral blood at the onset of the febrile attack. This is followed by anorexia, listlessness, depression and pyrexia.^{5, 7, 23, 27} Anaemia occurs occasionally in splenectomized calves. A Borrelia-like organism was found in the tick Ornithodoros coriaceus, and it was postulated that it might be a cause of bovine epizootic abortion.¹⁵ Spleen smears made from aborted bovine foetuses in South Africa have revealed Borrelia-like spirochaetes which may be the cause of sporadic bovine abortions.¹⁴

Pathology

A few non-specific lesions including slight lymph node enlargement and petechiae in pale mucous membranes have been described.¹³

Diagnosis, differential diagnosis and control

Spirochaetes are easily seen in blood smears and stain well with aniline dyes (Figures 133.1). ⁶ Clinically, borreliosis may be confused with mild cases of babesiosis, anaplasmosis and East Coast fever.^{4, 13} Concomitant infections by Babesia spp. often complicate the diagnosis.

Control of the disease can be accomplished by controlling the tick population.²² It has been shown in Zimbabwe that the prevalence of borreliosis is increased when the frequency of dipping is reduced.

References

1. ASSOKU, R.K.G., 1979. A study of the incidence of blood-borne parasites of livestock in Southern Ghana. Bulletin of Animal Health and Production in Africa, 27, 29–39.
2. BARBOUR, A.G. & HAYES, S.F., 1986. Biology of Borrelia species. Microbiological Reviews, 381–400
3. BARRÉ, N. & MOREL, P.C., 1983. Ticks (Acarina, Ixodoidea) of the Mascarene Islands and tick-borne diseases. Revue d’Élevage et de Médicine Vétérinaire des Pays Tropicaux, 36, 371–377.
4. BRUNER, D.W. & GILLESPIE, J.H., 1973. Hagan’s Infectious Diseases of Domestic Animals. London: Cornell University Press.
5. BRYSON, R.W. & WELLS, G.E., 1963. Spirochaetosis (Borreliosis) in a horse. Journal of the South African Veterinary Medical Association, 34, 103–104.
6. BUCHANAN, R.E. & GIBBONS, N.E., 1974. Bergey’s Manual of Determinative Bacteriology. 8th edn. Baltimore: The Williams & Wilkins Co
7. CALLOW, L.L., 1967. Observations on tick-transmitted spirochaetes of cattle in Australia and South Africa. British Veterinary Journal, 123, 492–496.
8. CANHAM, A.S., 1947. Spirochaetosis in pigs. Journal of the South African Veterinary Medical Association, 18, 32–38.
9. GREENE, R.T., LEVINE, J.F., BREITSCHWERDT, E.B. & BERKHOFF, H.A., 1980. Antibodies to Borrelia burgdorferi in dogs in North Carolina. American Journal of Veterinary Research, 49, 473–476.
10. GUGLIELMONE, A.A., AGUIRRE, D.H., MANGOLD, A.J. & GAIDO, A.B., 1987. Borrelia sp. in Boophilus microplus, the common tick of cattle, in Tucaman (Argentina). Veterinaria Argentina, 4, 248–249.
11. HOVMARK, A., ASBRINK, E., SCHWAN, O., HENDERSTEDT, B. & CHRISTENSSON, D., 1986. Antibodies to Borrelia spirochaetes in sera from Swedish cattle and sheep. Acta Veterinaria Scandinavica, 27, 479–485.
12. KASCHULA, V.R., 1948. Treponema theileri of a donkey and its transmission to a calf. Journal of the South African Veterinary Medical Association, 19, 100–102.
13. KIPTOON, J.C., MARIBEI, J.M., KAMUA, L.L.W. & THUO, P., 1979. Bovine borreliosis in Kenya: Borrelia theileri associated with bovine anaemia. Kenyan Veterinarian, 3, 11–12.
14. KITCHING, J.P. & BISHOP, G.C., 1980–1987. Allerton Regional Veterinary Laboratory, Pietermaritzburg, South Africa. Unpublished data.
15. LANE, R.S., BURDORFER, W., HAYES, S.F. & BARBOUR, A.G., 1985. Isolation of a spirochaete from the soft tick...