No abstract

Tick borne diseases (TBDs) are responsible for huge economic losses in cattle production in most African countries where the majority of cattle owners are the resource poor communal farmers. Governments have initiated and co-ordinate tick control programs with farmers required to contribute funds for their sustenance. The success of these programs will hinge upon the involvement of communal farmers in their design, implementation and evaluation. To this end, 313 communal farmers (approximately 8.4% of the target population) were interviewed and 3 focus group discussions were carried out in the southern low-veld part of Zimbabwe with the objectives of investigating communal farmers" perceptions on TBDs affecting cattle, level of participation in government initiated tick control programs, other tick control methods practiced, types of acaricides used and their perceived effectiveness. There was a general awareness of TBDs with 67.7% (n=212) farmers being able to describe tick diseases with names or clinical and post-mortem signs. The diseases or situations frequently associated with ticks were codwriosis (38%, n=119), mastitis (36.7%, n=115), anaplasmosis (36.1%, n=113), body damage (28.4%, n=89), babesiosis (24.6%, n=77) and poor body condition (16.6%, n=52). Cattle mortalities due to TBDs were reported by 23.8% (n=74) of the farmers. Farmers (40.6% , n=127) reported an increase in the number of cases of TBDs while 53.4% (n=167) did not see an increase. The plunge dip was consistently used by farmers (70.3%, n=220) to control ticks. Other tick control methods practiced were the hand spraying (67.4%, n=211), hand dressing (16.6%, n=52), traditional methods (5.4%, n=17), use of pour-ons (4.5%, n=14) and smearing (2.2%, n=7). The formamidines were the most common class of acaricide used (59.4%, n=186), followed by synthetic pyrethroids (29.1%, n=91), macro cyclic lactones (12.8%, n=40) and organophosphates (4.5%, n=14). Most farmers (75.2%, n=231) perceived these acaricides to be effective in controlling ticks. The results of focus group discussions showed that a number of factors influenced the success of government initiated tick control programs and these included inconsistent supply of acaricides, unaffordable dipping fees, lack of water, long distance to the dip tank, lack of information on dipping procedures and lack of knowledge on strategies for delaying acaricide resistance. This study demonstrates that while farmers can be a valuable source of information with regards to the epidemiology of tick borne diseases affecting their cattle, there is still need for further training in understanding the TBDs and strategies for their control.

No abstract

In total 7 567 were collected from 121 dip tanks in 12 districts representative of Zimbabwe's five ecological regions between September 2013 and May 2014. Based on morphological traits four genera and 13 species of ticks were identified. Amblyomma hebraeum (60.3%), Rhipicephalus microplus (58.7%), Rhipicephalus decoloratus (47.1%), Rhipicephalus appendiculatus (56.2%), Rhipicephalus evertsi evertsi (67.8%), Rhipicephalus (near) punctatus (13.2%), Hyalomma truncatum (38%) and Hyalomma rufipes (46.3%) were found in all the ecological regions of the country. Amblyomma variegatum and Rhipicephalus compositus (0.8%) were only found in the north central part of the country while Rhipicephalus simus (5%) had a sparse distribution. The Haemaphysalis leachi group (1.7%) and Rhipicephalus sanguineus (1.7%) were found whenever dogs were sampled suggesting these could be widespread throughout the country. The study confirmed the continued limited distribution of Amblyomma variegatum (3.3%) in the north central parts of the country, whereas A. hebraeum was found to have a wide distribution also encroaching areas of high rainfall and lower temperatures where it was not previously recorded. A parapatric relationship existed between these two Amblyomma species. Rhipicephalus appendiculatus was also widely distributed although its presence was dominant in the cooler and wetter parts of the country. The traditionally held view that Hyalomma species and R. evertsi evertsi can survive well under diverse conditions is upheld in this study. Rhipicephalus microplus was also present in dry regions but its adaptability to these regions requires further investigation.

Species distribution modelling is a very useful tool in vector management. Ticks are vectors of various pathogens which cause serious problems in livestock production in tropical countries. They have a high dispersal potential which is mainly facilitated by the movement of animals from one area to another. In light of the observed geographic expansion of Rhipicephalus microplus in Zimbabwe, we used species distribution modelling techniques to identify areas which may provide suitable habitats for the occurrence of this invasive tick species as well as the autochthonous Rhipicephalus decoloratus. Our results suggest that, despite the geographic expansion of R. microplus, climate will continue to be a limiting factor for the further expansion of this tick species. We expect its distribution to be restricted to the most favourable areas in the eastern and northern parts. The greater part of Zimbabwe is suitable for R. decoloratus, although in areas where R. microplus occurs, displacement of the former by the latter will be expected to occur. A heterogeneous climate, unregulated movement of cattle and episodic droughts are suggested to be possible factors for the continued existence of R. microplus and R. decoloratus in Zimbabwe and the partial displacement.