Besnoitia spp

From Cow
besnoitia cysts in skin, viewed under light microscopy
Chronic cutaneous Besnoitia infection in a cow

Besnoitia spp are a protozoan blood parasite which causes skin disease in cattle.

Bovine besnoitiosis leads to significant economic losses by a decline in milk production, sterility, transient or permanent infertility of bulls, skin lesions and increase of mortality in affected cattle population[1]. It is a disease with a high prevalence in tropical and subtropical regions and re-emerging in Europe[2].

Species of besnoitia which have been recognised as pathogenic in cattle include:

  • B. besnoiti (Europe, Africa, Asia, and South America)[3]
  • B. bennetti (Africa, north and south America, southern France)
  • B. jellisoni
  • B. wallacei
  • B. tarandi
  • B. darlingi
  • B. sauriana
  • B. caprae (Australia)

The organisms multiply in macrophages as well as in endothelial and other cells, producing characteristic large, thick-walled cysts filled with bradyzoites that develop into the invading tachyzoites.

Voles are thought to be the definitive host of this parasite and transmission to cattle is thought to be accidental[4].

Clinical signs

Most cattle are subclinically affected, with small cystic lesions in the scleral conjunctiva. Fever, lymphadenopathy, diarrhea, anorexia and orchitis have been reported.

Skin lesions may be noted, such as pruritus and alopecia. Bulls which have orchitis are usually rendered infertile.

Diagnosis

Diagnosis is made on presenting clinical signs. Confirmatory diagnosis is made with modified agglutination[5], ELISA[6] and PCR assays[7].

Treatment

In cattle which are valuable, therapeutic effects of tetracyclines have been noted.

References

  1. Olias P et al (2011) Molecular pathology, taxonomy and epidemiology of Besnoitia species (Protozoa: Sarcocystidae). Infect Genet Evol 11(7):1564-1576
  2. Marcelino E et al(2011) Besnoitia besnoiti protein disulfide isomerase (BbPDI): molecular characterization, expression and in silico modelling. Exp Parasitol 129(2):164-174
  3. Gentile A et al (2012) Evidence for bovine besnoitiosis being endemic in Italy--first in vitro isolation of Besnoitia besnoiti from cattle born in Italy. Vet Parasitol 184(2-4):108-115
  4. Basso W et al (2011) Exploring the life cycle of Besnoitia besnoiti - experimental infection of putative definitive and intermediate host species. Vet Parasitol 178(3-4):223-234
  5. Waap H et al (2011) A modified agglutination test for the diagnosis of Besnoitia besnoiti infection. Vet Parasitol 178(3-4):217-222
  6. Nasir A et al (2012) Sero-prevalence of Neospora caninum and Besnoitia besnoiti in South Australian beef and dairy cattle. Vet Parasitol 186(3-4):480-485
  7. Schares G et al (2011) Quantitative real time polymerase chain reaction assays for the sensitive detection of Besnoitia besnoiti infection in cattle. Vet Parasitol 178(3-4):208-216