Prospective Study for the Detection of Anaplasma marginale Theiler, 1911 (Rickettsiales: Anaplasmataceae) in Costa Rica^a

Abstract

A prospective study was conducted to assess the dynamics of the infection and host response to Anaplasma marginale in one closed herd in the dry tropical forest of Costa Rica. The study subjects were the dams and their calves born during 1 breeding season (1995-1996). All cows were sampled at 3 month intervals for antibody detection using a competitive ELISA (cELISA) and for antigen detection using PCR/nonradioactive probe assay. All 24 calves born during the study were individually identified at birth and subsequently sampled each month for PCR and cELISA. Ticks were identified from all animals throughout the entire study period. The results from this study confirmed that the cELISA is a reliable assay for identifying new and carrier infections and that carrier infections can exist at levels below that detectable by PCR. In addition, it was demonstrated that calves born in this region will most likely be exposed to Anaplasma within the first 6 months of age.

Prevalence of Anaplasma ovis infection in Angora goats of Duhok province, Kurdistan region-Iraq

“…It has been reported that sheep and goats of all age's groups are susceptible to A. ovis infection, but older animals may suffer from a greater reduction in hematocrit values (17). Young animals probably become infected early, develop immunity and serve as reservoirs of infection for other animals (31). The results of the present study were completely in line with the findings of (12,20), who reported that adult animals were more susceptible to anaplasmosis infection than younger animal.…”

Molecular and serological prevalence of Anaplasma marginale in cattle of North Central Morocco

“…Cattle of all ages are susceptible to anaplasmosis but the severity of the infection is directly related to age, with older animals suffering more severe clinical disease. Indeed, in this survey prevalence in young animals was similar to older animals consistent with previous reports in Costa Rica (Pérez et al, 1994;Herrero et al, 1998) and Brazil (Barros et al, 2005). Young animals probably become infected early, develop immunity and serve as reservoirs of infection for other animals (Herrero et al, 1998).…”

“…These discrepancies could be explained by differences in the timing of the parasite presence and the antibody responses in the infected animals as well as the stage of infection. During chronic infection antibodies remain in the circulating blood for a longer period even after a decrease in parasitemia below detection even by PCR or after parasite clearance (Herrero et al, 1998). Conversely, samples positive by nPCR and negative by serology most likely represent recent infection prior to the development of antibody.…”

“…Anaplasmosis has been reported in different regions of Morocco (Verhulst et al, 1983;Sahibi et al, 1998b), but it has a perceived lower incidence compared with theileriosis and babesiosis. Although, severe economic losses have been reported due to anaplasmosis outbreaks in several parts of the world (Herrero et al, 1998;Kocan et al, 2000Kocan et al, , 2004Grisi et al, 2002;Jongejan and Uilenberg, 2004), no specific disease outbreak of A. marginale in cattle has been reported in Morocco and the only epidemiological studies of anaplasmosis reported previously were conducted more than a decade ago (Sahibi et al, 1998b).…”

Comparison of cELISA and IFA tests in the serodiagnosis of anaplasmosis in cattle

“…The MSP-5 antigen is conserved among all known species of Anaplasma (Visser et al, 1992). In a study (Herrero et al, 1998) where PCR and cELISA were compared for the diagnosis of antibodies specific to Anaplasma in cattle sera, it has been stated that these two tests are in accordant with each other.…”