Babesia bovis in Large Ruminants in Pakistan - Molecular Detection and Haemato-Biochemical Alterations

Abstract

Background: Babesiosis is endemic in Pakistan and is one of the most important bovine diseases that causes huge economic losses and high mortality in young animals. A hematobiochemical study was conducted to unveil the difference between diseased and healthy animals in selected districts i.e., Faisalabad (31° 25' 7.3740'' N and 73° 4' 44.7924'' E), Toba Tek Singh (30° 58' 9.7392'' N and 72° 27' 40.7484'' E) and Jhang (31° 16' 40.9656'' N and 72° 18' 42.3360'' E) of Punjab, Pakistan.

Materials, Methods & Results: A total of 518 (Cattle = 360, Buffalo = 158) blood samples were collected. The samples were analyzed by polymerase chain reaction (PCR) targeting apocytochrome b-gene (Babesia bovis-gene) (CYTb) followed by haemato-biochemical analysis. Chi-square test for univariate analysis was used to analyze the data. In summer the PCR-based prevalence was 29.4 (53/180) and 24.05% (19/79) in cows and buffaloes, respectively. On the other hand, in winter results showed that 12.7 (23/180), 13.92 % (11/79) samples positive for Babesia genus from cows and buffaloes, respectively. The positive samples were further investigated for hematological and biochemical analysis. The results revealed that, the mean value of hematological parameters like RBCs, Hb, PCV, MCV and MCHC was significantly (P < 0.05) decreased in infected animals (cows and buffaloes) as compared to the non-infected ones. While the biochemical parameters like Alanine aminotransferase (ALT), Aspartate aminotransferase (AST), cholesterol and Lactate dehydrogenase were significantly (P < 0.05) increased in infected animals as compared to healthy animals. This study is the first molecular and hematobiochemical evidence of Babesia bovis in dairy herds of Punjab province, Pakistan.

Discussion: Bovine babesiosis is one of the important tick-borne diseases (TBD) affecting dairy industry. In bovines, among 3 Babesia species that cause the disease B. bovis is more pathogenic with high mortality and morbidity. Pakistan is situated in tropical and sub-tropical region where the humidity is high in some part of countries. This high humidity mostly favors the reproduction of the ticks thus higher prevalence of TBDs in this region. Initially the babesiosis was diagnosed by light microscopy using thin blood smear stained with Giemsa stain. Many studies verified that PCR is a more specific and sensitive tool than conventional techniques for the detection of carrier / asymptomatic ruminants. The haemato-biochemical profile is another valuable footprint to track the disease. Keeping in view the above-mentioned fact the present project has been planned to evaluate the haemato-biochemical alteration between health and Babesia infected cattle along with the molecular detection of Babesia species involved in bovine babesiosis. The mean values of haemato-biochemical parameters in clinically ill and healthy animals revealed that the mean values of hematological parameters like RBCs, Hb, PCV, and HCT were significantly decreased in diseased animals as compared to the healthy ones. All these might be due the fact that the parasite is intra-erythrocytic in nature and destruction of red blood cells results in significant (P < 0.05) decrease level of all the hematological parameters. The mean value of ALT in babesiosis infected cattle was significantly higher as compared to healthy cattle. The mean values of AST and LDH in babesiosis infected cows was significantly higher as compared to that in healthy cows. The elevation in liver enzymes in babesiosis may be due to the hepatic damage and lesions induced by the parasite during its multiplication in the blood followed by disturbed liver function. These enzymes are present in high concentrations in the muscles and liver. High level of these enzymes in the blood is indicator of organ necrosis or damage.

Keywords: bovines, buffaloes, tick-borne diseases, babesiosis, liver enzymes, PCR.