The seasonality as a relevant aspect to be considered for differential diagnosis of Trypanosoma vivax infection and co-infections in female cattle.

Bovine Trypanosomiasis and other infectious diseases cause relevant loss for the livestock industry impacting productive/reproductive indices. This study intended to better understand the frequency, seasonality, and profile of infections associated with Bovine Trypanosomiasis. A total of 1443 serum samples were screened for T. vivax infection and other infectious diseases: Neosporosis, Leptospirosis, Bovine Leukosis Virus infection/(BLV), Infectious Bovine Rhinotracheitis/(IBR) or Bovine Viral Diarrhea/(BVD). Distinct methods were used for screening and diagnosis: immunofluorescence assay (Trypanosomiasis), ELISA (Neosporosis,BLV,IBR,BVD) and microscopic agglutination test (Leptospirosis). Our findings demonstrated that the seropositivity for Trypanosomiasis=57% was similar to Neosporosis=55%, higher than Leptospirosis=39% and BVL=34%, but lower than IBR=88% and BVD=71%. The seropositivity for Trypanosomiasis was higher in the autumn and lower in the winter. Regardless the season, the IBR seropositivity (min=73%;max=95%) was higher than Trypanosomiasis (min=48%;max=68%). Moreover, Neosporosis (min=71%;max=100%) and BVD (min=65%;max=76%) were more frequent than Trypanosomiasis in the summer, winter and spring. The diagnosis outcome revealed that Trypanosomiasis&IBR=43% and Trypanosomiasis&Neosporosis=35% were the most frequent co-infections with higher seropositivity in the autumn (58%) and summer (80%), respectively. Noteworthy, high seropositivity to Trypanosomiasis&BVD was registered in the autumn (46%). Together, our data re-enforce the relevance of differential diagnosis between Trypanosomiasis with other bovine infectious diseases and that differences in the seasonality profile is a relevant aspect to be considered while selecting the differential diagnosis to be applied.

Methods Applied to the Diagnosis of Cattle Trypanosoma vivax Infection: An Overview of the Current State of the Art.

Bovine trypanosomiasis caused by Trypanosoma vivax is a relevant disease in domestic ungulates in Latin America, causing different types of livestock losses, particularly in African and South American countries, leading to loss of millions of dollars/year related to dairy and meat production. In addition, T. vivax trypanosomiasis requires intensive veterinary care. While vector control is a feasible measure to manage disease spreading, the search for accurate diagnostic tools still represents a gap in routine veterinary practices and a challenge for the scientific community. The parasite is mechanically transmitted by fomites or by the saliva of haematophagous flies, such as Stomoxys sp. and Tabanus sp., infecting cattle as well as a number of animal hosts. The main symptoms of T. vivax bovine trypanosomiasis are apathy, fever, restricted growth, miscarriage, progressive weakness, neurological signs, pale mucous, loss of appetite, lethargy, and substantial weight loss. In most cases, the presence of animals with subclinical infections, nonspecific symptoms and without apparent parasitaemia presents a challenge when making a diagnosis, which requires accurate methods. Herein, we review state of the art concerning current methods available for the diagnosis of T. vivax bovine trypanosomiasis, focusing on clinical, parasitological, immunological and molecular approaches, highlighting the main features of each method, including "pros and cons". Overall, combining several diagnostic techniques is a better choice since it leads to fewer false negative results and contributes to better disease control.