The control of ticks and tick-borne diseases in Mozambique

Alfredo, Alberto Albino Nota (2005). The control of ticks and tick-borne diseases in Mozambique MPhil Thesis, School of Veterinary Science, The University of Queensland.

       
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Author Alfredo, Alberto Albino Nota
Thesis Title The control of ticks and tick-borne diseases in Mozambique
School, Centre or Institute School of Veterinary Science
Institution The University of Queensland
Publication date 2005
Thesis type MPhil Thesis
Supervisor Nicholas Jonsson
Total pages 201
Collection year 2005
Language eng
Subjects L
300508 Parasitology
780105 Biological sciences
Formatted abstract

The purpose of this project was to produce sound epidemiological and farming system evidence for re-formulation of tick control policies in Mozambique. To attain this goal three main studies were undertaken. 

 

The first study was a survey of traditional farmers regarding animal management and their attitudes to, and methods for, controlling ticks and tick-borne diseases (TBDs). This was conducted in the northwestern province of Tete, on the border with Malawi, Zambia and Zimbabwe using a questionnaire directly administered to 213 randomly selected cattle owners and/or herd managers. This study group was found in randomly chosen villages in five purposefully selected districts including highland Angonia, semi-arid southwestern and central districts of Changara, Moatize and City council of Tete and high rainfall south-eastern central lowland district of Mutarara. Quantitative and qualitative information was obtained from herd managers about their production system, their perceptions of the main production constraints, livestock diseases and the control of ticks and TBDs in their cattle. The predominant farming system was mixed crop-livestock with farmers owning an average of 18.5 local cattle grazed in communal land and kept in kraals overnight. It was clear that cattle play an important socio-economic role in rural communities in the study areas, with the majority farming cattle for social and emergency purposes, as savings and investment. 

 

Although the region is considered to be semi-arid and prone to drought, pasture, land and water were not great concerns to producers, suggesting that the local cattle are well adapted to harsh conditions. However, in general, the majority of interviewees believed disease (79.2%), veterinary assistance costs (75.6%) and thieves (57.7%) were major constraints to cattle production. Among common health problems, ticks and the diseases they transmit were of great concern to nearly all (99.5%) interviewees. Regarding the effect of ticks, most believed them to transmit diseases (77%), to downgrade hides (76.5%) and to cause anaemia (30%). The majority of cattle owners or managers did not know which type of acaricide was used in the dip tank in their village, however a few indicated that they used synthetic pyrethroids (9.5%) or ethion (4.5%) and chlorphenvinfos (3.6%). About one quarter of interviewees did not use acaricidal tick control. Regarding the acaricidal application regime recommended by DINAP, the national veterinary authority, the study confirmed that most cattle owners and managers were aware that the legislation required weekly dipping. However, few (9.5%) complied with that regime. Most dipped or treated cattle to protect them from ticks and TBDs, according to the tick load on cattle. Reasons indicated for non-compliance with the dipping program included dip cost, time for crop production, lack of labour for mustering animals and low tick infestations on cattle. Most cattle owners and managers did not use alternatives to acaricides for tick control. 

 

Secondly, a survey of dip tank attendants was conducted concurrent with the first survey in randomly selected villages. A total of 19 dip tank attendants were interviewed. The focus of this study was to identify current tick control practice by government, constraint factors of tick management and perceptions of dip tank attendants toward ticks and tick-borne disease. It was confirmed that the attendance at the dip pen on specified days was poor as only an average of302 out of 2,139 cattle existing in dip tank dependent villages were presented for dipping on the survey day. Similar to farmer perception, despite the aridity that characterises most agroecological zones of this study, water was not one of the most important constraints for either cattle production or dipping operation. This could be attributed to the existence of a considerable number of rivers with permanent water (such as the Zambezi river which crosses north Changara, Tete city, Moatize and Mutarara; confluent rivers Revubue in Moatize and Luenha river in southern Changara and Mahowe river in Angonia). Beside TBDs, helminthosis and malnutrition were consistently cited as problems thongh consistently ranked lower in importance. Boophilus species were well known among diptank attendants, although ability to differentiate between B. microplus and B. decoloratus was not tested. Other tick species descriptions were only provided by the interviewees from agro-ecological zones where the species are common. Farmers and dip tank attendants thought that the maximum number of engorged ticks was low (<10 ), suggesting that there is a high degree of tick-resistance in the indigenous sanga and zebu cattle of Tete. This is likely to be one of the factors contributing to the low level of participation by cattle owners and managers in the government directed dipping program. Acaricides continue to be the basis of tick control in Mozambique. Dipping was occasionally disrupted in at least 14 dip tanks for reasons including: shortage of acaride and water, flooding and physical damage. The main acaricide used was ethion, followed by chlorfenvinphos and flumethrin. All dip tanks were recharged at six monthly intervals. No dip testing facilities were available. There were some concerns about human safety in relation to dip management. Although most acaricides were stocked at dip tanks, nearly half indicated that they were kept in the home or office. Additionally, no protective clothing and footwear or masks were provided to diptank operators. 

 

The third study was a serological survey of bovine babesiosis and anaplasmosis in communal cattle in the northwestern province of Tete, Mozambique. Blood was collected from cattle ranging from 6 to 18 months of age from randomly selected farms from six districts. Thirty-nine percent of all 478 calves tested in Tete Province were seropositive to the ELISA test for B. bovis antibodies and 63% of all calves were seropositive for A. marginate. Seroprevalence of B. bovis ranged from 22.8% in Tete City District to 48.1% in Angonia District. For A. marginate, it ranged from 34.4% in Angonia District to 87.3% in Moatize District. The dominant factor affecting seroprevalence for both haemoparasites was district and there was a trend for higher intensity of tick control to be associated with higher seroprevalence of B. bovis and lower seroprevalence of A. marginate. The obvious differences were the low prevalence of B. bovis in Tete City District and the low prevalence of A. marginate in Angonia District. The levels of exposure to B. bovis seen in our study are well below any that could be considered to be consistent with endemic stability, yet they are sufficiently high to ensure that clinical disease would be a risk. The seroprevalence of A. marginate, however, suggests that endemic stability with respect to this disease could exist in districts other than Angonia. There was no strong and consistent relationship between the intensity of control and the likelihood of seropositivity to either of the diseases. 

Keyword Ticks -- Mozambique.
Ticks as carriers of disease -- Mozambique.

 
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