Distribution and abundance of ticks on cattle and associated tick-borne pathogens from Kilombero and Iringa districts in Tanzania

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Date

2023

Journal Title

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Publisher

Sokoine University of Agriculture

Abstract

Ticks are a major group of arthropod vectors that transmit pathogens that cause devastating diseases in humans and animals. The information on tick infestation and related tick-borne pathogens in Tanzania is insufficient. Therefore, this study was conducted to determine tick prevalence and degree of infestation on cattle as well as associated tick-borne pathogens, in Kilombero and Iringa districts of Tanzania. A repeated cross-sectional study was conducted to collect ticks on cattle in wet and dry seasons from January to August 2021. Out of 740 cattle examined, 304 were infested with ticks. In total 1,780 ticks were counted on one side of the animal’s body and doubled, whereby a total of 3,560 ticks were recorded. A total of 1,889 tick were collected from the infected cattle including 109 more tick observed while collecting ticks based on the animal’s posture when restrained on ground. Thereafter, ticks were identified morphologically using published morphological keys under a stereomicroscope and confirmed using polymerase chain reaction (PCR) and sequencing of the mitochondrial CO1 and 16S rRNA genes. The tick-borne pathogens were detected using PCR. Fisher’s exact test was performed to detect the difference between the proportion of hard tick species and the study areas and season. One-way ANOVA was performed to compare mean tick burden between variables (including cattle age groups, body condition score and frequency of tick control). Out of 1,889 ticks, 1,377 fit in the genus Rhipicephalus, 459 in the genus Amblyomma and 53 in the genus Hyalomma. The most prevalent tick species identified were Rhipicephalus microplus (48.1%), Rhipicephalus evertsi (16.4%), and Amblyomma lepidum (16.4%). The sequencing results of the mitochondrial DNA fragments indicated high nucleotide identity (96-100%) with sequences in GenBank and Barcode of Life Database (BOLD) (OM974109-OM974112 and OM978262-OM978265). Seasonality results indicate no statistically significant difference in the prevalence of tick infestation on cattle during the dry (41.05%) and wet (41.11%) seasons. The DNA of Anaplasma spp. and Theileria/Babesia spp. were detected in (70.33%, n=64) of all tick pools. The detection rate of both Anaplasma and Theileria/Babesia spp. was high in Amblyomma lepidum (25.00%, n=16) followed by Rhipicephalus evertsi (23.44%, n=15) tick pools. The results showed high tick prevalence and abundance on cattle suggesting increased risk of tick- borne disease transmissions and reduced animal production and productivity. Therefore, tick infestation in the study areas highlight the need for strategic tick control approaches.

Description

Masters Dissertations

Keywords

ticks, cattle, Iringa districts, animals, tick-borne

Citation