Clinical and Serological Dynamics ofBesnoitia besnoitiInfection in Three Endemically Infected Beef Cattle Herds

Abstract

The dynamics of bovine besnoitiosis were studied in an area where the disease is endemic. A four-year longitudinal study was conducted for the first time in three infected beef cattle herds located in the Urbasa-Andía Mountains (Navarra, Spain). Each herd was visited four to seven times, and clinical and serological prevalence rates and incidence rates were estimated. Clinical inspections to identify compatible clinical signs with the disease stages were conducted at the beginning and end of the study. Serological assessment was initially performed by ELISA. Seronegative animals with clinical signs and seropositive animals with relative index per cent (RIPC) values lower than 30 that did not increase during the study period were analysed by Western blot to optimize the sensitivity and specificity of the ELISA test. Clinical prevalence rates were slightly higher (62% on average) than the seroprevalence rates (50% on average), and tissue cysts located in the vestibulum vaginae and sclera were the most frequently detected clinical signs. The proportion of seropositive animals with clinical signs varied from 16.7% to 73.6% among the herds, and 17% of cattle with clinical signs proved to be seronegative by both serological tests. An average 22% serological incidence rate was also reported in addition to clinical incidence rates that varied from 12.5% to 16.7%. Additionally, parasitemia was investigated in the herd that showed the highest clinical and seroprevalence rates. Only one PCR positive blood sample was detected. Thus, the role that blood may play in parasite transmission needs to be further investigated. Infected herds maintained both high prevalence and incidence rates in the absence of control measures and a high number of parasite carriers. Finally, economic impact studies on reproductive and productive losses associated with besnoitiosis need to be performed to implement a cost-benefit control programme.

Bovine besnoitiosis (Besnoitia besnoiti) in an Irish dairy herd

“…This has not been described in European beef calves affected, and, given the comparatively small number of calves examined (N=31) and tested (N=15), further investigation and follow-up is warranted to confirm this finding. The greater percentage of seropositive compared with clinically affected cows in this dairy herd contrasts with the clinical and serological findings of a recent four-year longitudinal Spanish study involving three endemically infected beef herds, which found that clinical prevalence rates were slightly higher than seroprevalence rates (Gutiérrez-Expósito and others 2015). …”

Naturally acquired bovine besnoitiosis: Disease frequency, risk and outcome in an endemically infected beef herd

“…The average seroprevalence in Herd‐BbGer1 was 95% over the entire time of 4 years, and it was considerably higher than the average clinical prevalence, which was 27%. The average seroprevalence is considered very high, especially when compared with an another 4‐year study, which reported an average seroprevalence of 50% (Gutiérrez‐Expósito, Ortega‐Mora, et al., ). However, the inter‐herd prevalences may differ largely between herds and values above 90% are not unusual, especially in outbreak situations (Fernández‐García et al., ; Gutiérrez‐Expósito, Ortega‐Mora, et al., ).…”

“…Most infected animals display only mild clinical lesions, that is, pathognomonic SC or VV cysts, or are subclinically infected (Bigalke, ; Gutiérrez‐Expósito, Ortega‐Mora, et al., ; Jacquiet, Liénard, & Franc, ). Serological and PCR protocols have been established to detect B. besnoiti‐ specific antibodies and DNA to confirm clinical diagnoses and detect a majority of subclinical carriers (Cortes et al., ; Fernández‐García et al., ; García‐Lunar et al., ; Schares et al., ; Schares, Basso, et al., ; Schares et al., ).…”

“…The use of specific serological tests allowed large‐scale herd examinations and comparative analyses of variations in seroprevalence with regard to different cattle management systems, age groups and gender, or the comparison of clinical prevalence and seroprevalence (Fernández‐García et al., ; García‐Lunar, Ortega‐Mora, Schares, Diezma‐Díaz, & Álvarez‐García, ; Goldman & Pipano, ; Gutiérrez‐Expósito, Ortega‐Mora, et al., ; Liénard et al., ; Ryan et al., ). The different studies on clinical and serological prevalences have been recently reviewed (Gutiérrez‐Expósito, Ferre, Ortega‐Mora, & Álvarez‐García, ).…”

Serological dynamics and risk factors of Besnoitia besnoiti infection in breeding bulls from an endemically infected purebred beef herd

“…In an endemic area in Spain, the intra-herd prevalence increased from 34.3 to 42.5% within 4 months (Nieto-Rodríguez et al 2016) and in a study carried out in south-western France, the intra-herd seroprevalence increased from 29.8 to 89.5% in less than 2 years of observation (Lienard et al 2011). Similarly, in a 4-year study, an annual incidence of 12.5-62.5% was registered in three endemically infected beef herds in which prevalence varied from 35.6 to 86.5% (Gutiérrez-Expósito et al 2015 ig. 2 a Histological section of skin: hyperkeratosis with lymphohistiocytic and eosinophilic flogosis.…”