Sammanfattning

Point-source infections are most likely the cause for Neospora caninum-induced abortion outbreaks in cattle, whereas an increased annual abortion rate may be a consequence of vertical transmission. The aims of the present study were to examine the reproductive effects of neosporosis in a beef herd for 3 years, after a point-source outbreak and to use IgG avidity serology to examine the chronicity of infections and patterns of transmission. During the study, 76-78% of animals were seropositive for N. caninum. The pregnancy rate varied from 88% to 94%, without any reduction in the pregnancy rate of seropositive cows compared with seronegative cows. The annual abortion rate was 2.5-5.5%, and all but 1 abortion occurred in seropositive dams. The efficiency of vertical transmission was estimated to be 85%. Several calves, born to seronegative dams, were seropositive at 6-13 months of age, indicating a 22% mean annual rate of horizontal transmission. The mean avidity in seropositive cows increased from 30 during the initial outbreak to 74 after 3 years. The mode of IgG avidity was 21-40 during the initial abortion outbreak, 41-60 after 1 year, and 61-80 after 2 and 3 years. The results reveal high annual rates of both vertical and horizontal transmission of N. caninum in a herd of beef cows and provide further validation on the ability of the N. caninum IgG avidity ELISA to accurately assess the chronicity of infection

Publicerad i

Journal of Veterinary Diagnostic Investigation
2003, Volym: 15, nummer: 1, sidor: 3-7
Utgivare: AMER ASSOC VETERINARY LABORATORY DIAGNOSTICIANS INC

SLU författare

• Björkman, Camilla

  • Institutionen för kliniska vetenskaper, Sveriges lantbruksuniversitet
    

• Frössling, Jenny

  • Institutionen för kliniska vetenskaper, Sveriges lantbruksuniversitet
    

• Uggla, Arvid

  • Institutionen för husdjurens biovetenskaper, Sveriges lantbruksuniversitet
    

Permanent länk till denna sida (URI)

https://res.slu.se/id/publ/94