Search

Tick-borne pathogens (TBPs) in dogs have attracted much attention over the last decade since some are now known to be zoonotic and pose a threat to both animal and human health sectors. Despite the increase in the number of studies on canine TBPs worldwide, only a few studies have been conducted in resource-limited countries where research priority is given to food animals than companion animals. In the present study, the occurrence of TBPs of the genera Babesia, Hepatozoon, Anaplasma, and Ehrlichia was investigated in 209 owned and stray dogs in three major cities in Malawi through molecular techniques. Among the examined dogs, 93 (44.5%) were infected with at least one TBP. The detection rates were 23.1% for Babesia rossi, 2.9% for B. vogeli, 19.1% for Hepatozoon canis, 2.4% for Anaplasma platys, and 3.8% for Ehrlichia canis. This is the first molecular study that has provided evidence that dogs in Malawi are infected with TBPs. Sensitization is required for veterinary practitioners, dog handlers, and pet owners as the detected pathogens affect the animals' wellbeing. Further studies focusing on rural areas with limited or no access to veterinary care are required to ascertain the extent of the TBP infection in dogs. [ABSTRACT FROM AUTHOR]

East Coast fever (ECF) is an acute fatal tick-borne disease of cattle caused by Theileria parva. It causes major losses in exotic and crossbreed cattle, but this could be prevented by a vaccine of T. parva if the vaccine is selected properly based on information from molecular epidemiology studies. The Muguga cocktail (MC) vaccine (Muguga, Kiambu 5 and Serengeti-transformed strains) has been used on exotic and crossbreed cattle. A total of 254 T. parva samples from vaccinated and unvaccinated cattle were used to understand the genetic diversity of T. parva in Malawi using partial sequences of the Tp1 and Tp2 genes encoding T. parva CD8+ antigens, known to be immunodominant and current candidate antigens for a subunit vaccine. Single nucleotide polymorphisms were observed at 14 positions (3.65%) in Tp1 and 156 positions (33.12%) in Tp2, plus short deletions in Tp1, resulting in 6 and 10 amino acid variants in the Tp1 and Tp2 genes, respectively. Most sequences were either identical or similar to T. parva Muguga and Kiambu 5 strains. This may suggest the possible expansion of vaccine components into unvaccinated cattle, or that a very similar genotype already existed in Malawi. This study provides information that support the use of MC to control ECF in Malawi. [ABSTRACT FROM AUTHOR]

• Cattle was screened for Anaplasmataceae and piroplasms using heat shock protein gene and 18S rDNA, respectively. • Among the animals, 92.3% (177/191) were infected with at least one tick-borne pathogen. • A new multiplex PCR assay for Babesia and Theileria species identification was designed. • First report of Anaplasma platys infection in cattle in southern Africa. Malawi has an estimated cattle population of 1,884,803 heads, the indigenous Malawi zebu breed accounts for 91.2%, while the exotic and crossbred accounts for the remaining 8.8%. Although ticks and tick-borne diseases are widespread in Malawi, no molecular study has been conducted to investigate the tick-borne Anaplasmataceae and piroplasms infecting cattle. To provide an insight into the current status of tick-borne pathogens (TBPs) of cattle, a molecular survey was conducted in the central and southern regions of Malawi. A total of 191 cattle of which 132 were Malawi zebu, 44 were Holstein Friesian and 15 were Holstein-Friesian/ Malawi zebu crosses were screened for Anaplasmataceae and piroplasms using the heat shock protein groEL gene and 18S rDNA, respectively. A new 18S rDNA multiplex PCR assay was designed for Babesia and Theileria species identification without sequencing. Overall, 92.3% (n = 177) of the examined animals were infected with at least one TBP. Anaplasmataceae-positive rate was 57.6% (n = 110) while for piroplasms it was 80.1% (n = 153). The detected Anaplasmataceae were Anaplasma bovis 2.6% (n = 5), Anaplasma marginale 24.6% (n = 47), Anaplasma platys -like 13.6% (n = 26), uncharacterized Anaplasma sp. 14.1% (n = 27), and uncharacterized Ehrlichia sp. 16.2% (n = 31). The detected piroplasms were Babesia bigemina 2.6% (n = 5), Theileria mutans 73.8% (n = 141), Theileria parva 33.0% (n = 63), Theileria taurotragi 12.6% (n = 24), and Theileria velifera 53.4% (n = 102). Mixed infection rate was found in 79.6% (n = 152) of the samples analyzed. This study has shown a high burden of TBPs among cattle in Malawi which highlights the need to conceive new methods to control ticks and TBPs in order to improve animal health and productivity. The newly developed multiplex PCR assay would be a useful tool especially in resource limited settings where sequencing is not available and when mixed infections are expected. [Display omitted] [ABSTRACT FROM AUTHOR]

Tick-borne diseases (TBDs) caused by pathogens belonging to the genera Anaplasma, Ehrlichia, Babesia and Theileria in small ruminants are widespread in the tropical and sub-tropical countries. The epidemiology of tick-borne pathogens (TBPs) in small ruminants is less understood compared to those infecting cattle in general. This study was carried out to investigate and characterize TBPs in sheep and goats using molecular tools. A total of 107 blood samples from sheep (n = 8) and goats (n = 99) were collected from animals that were apparently healthy from two farms in the central and the southern regions of Malawi. The V4 hypervariable region of the 18S ribosomal RNA gene (rDNA) and the V1 hypervariable region of the 16S rDNA polymerase chain reaction (PCR) assays were used for detection of tick-borne piroplasms and Anaplasmataceae, respectively. Almost the full-length 18S rDNA and the heat shock protein (groEL) gene sequences were used for genetic characterization of the piroplasms and Anaplasmataceae, respectively. The results showed that 76.6 % of the examined animals (n = 107) were positive for at least one TBP. The overall co-infection with at least two TBPs was observed in forty-eight animals (45 %). The detected TBPs were Anaplasma ovis (65 %), Ehrlichia ruminantium (4%), Ehrlichia canis (2%), Babesia strain closely related to Babesia gibsoni (1%), Theileria ovis (52 %), Theileria mutans (3%), Theileria separata (2%), Anaplasma sp. (1%) and Theileria sp. strain MSD-like (17 %). To the authors knowledge this is the first molecular study of TBPs in sheep and goats in Malawi. These results have therefore provided a significant milestone in the knowledge of occurrence of TBPs in sheep and goats in Malawi, which is prerequisite to proper diagnosis and control., (Copyright © 2020 Elsevier GmbH. All rights reserved.)