Immunization against Lamb Haemonchosis with a Recombinant Somatic Antigen of Haemonchus contortus (rHcp26/23).

Haemonchosis, caused by the abomasal nematode Haemonchus contortus, is a common parasitic disease of sheep. Our previous results showed that a soluble fraction from adult stages of the nematode (p26/23) induced partial protection against challenge. Recombinant DNA technology was applied to obtain a synthetic protein (rHcp26/23). Immunological assays (ELISA, Western blotting, and immunolocalization), using sera from lambs immunized with p26/23, confirmed the identity of the recombinant protein and demonstrated that the synthetic protein is equivalent to the purified protein employed in the previous immunoprophylaxis studies. Vaccination of lambs with 300 mug of rHcp26/23 and Freund's adjuvant elicited a notable specific antibody response. Immunization did not induce any significant protection after challenge with 16000 infective larvae of H. contortus, and comparable values for parasite faecal egg output, packed cell volume, and abomasal parasite burdens were found in vaccinated and control animals.

Haemonchus contortus-sheep relationship: a review

La hemoncosis, causada por el nematodo del abomaso de rumiantes Haemonchus contortus, constituye una de las enfermedades parasitarias más notables del ganado ovino en todo el mundo. Las infecciones provocan síndromes anémicos y de mala digestión/absorción que pueden causar la muerte en los casos agudos y disminución de la producción en las formas crónicas. Las claves principales para la aparición de esta enfermedad son el comportamiento biológico del helmito, su patogenia, además de la respuesta del hospedador. El conocimiento actualizado de estos aspectos permitirá una mayor eficaciencia de los métodos de diagnóstico y contro del proceso y, como consecuencia, la disminución de los riesgos de aparición de esta enfermedad. La presente revisión analiza y discute algunos aspectos de la relación ganado ovino-H. contortus de interés para disminuir el impacto de esta parasitosis sobre la salud y producción ganaderas.

Haemonchosis, caused by the abomasal nematode Haemonchus contortus, is among the most relevant parasitic diseases of small ruminants all over the world. The infections are responsible for anemic and bad digestion/absorption syndromes causing the death of severely infected animals in acute cases and the reduction of production scores in the chronic forms of the disease. The keys for the appearance of the disease include the biological behavior of the helminth and mechanisms of pathogenesis, besides the host’s response. The updated knowledge of these aspects would result in a higher efficiency of diagnostic and control methods, thus reducing the risks of appearance of the disease. In the present review, several aspects of the sheep - H. contortus relationship are analyzed with the aim of reducing the impact of this parasitosis on livestock health and productivity.