Hope for tick disease victims: Researchers to develop vaccine
It was in 1964 that the Government of Uganda launched the first ever large-scale compulsory tick control scheme in Kyaggwe, involving 44,000 cattle which were sprayed in 97 spraying centres. This Scheme was financed by USAID and acaricide was free. The scheme was considered successful and the indigenous cattle population increased from 44,000 (I 964) to 55,000 (1966). Exotic cattle increased from 750 in 1964 to2,300 in 1967.
The long cry of animal husbandry farmers across the country and the neighbouring countries will soon be no more. This follows efforts by scientists at the National Agricultural Research Organisation (Naro) making a breakthrough in developing anti-tick vaccines against tick-borne diseases.
Scientists at the National Livestock Resources Research Institute (NaLRRI) have been conducting research since 2016 in a bid to come up with a vaccine to save farmers from the burden of tick-bone diseases.
The control of ticks and tick-borne diseases has been sophisticated by mainly restricting cattle movement and use of acaricides which are applied on animals in dips, or as sprays and hand dressing.
The scientists are now at the stage of on station trials at the Institute and thereafter move to field stations for possible release by next year.
The tick burden
The lead investigator of the Anti- tick vaccine development, Dr. Fredrick Kabi, explaining about the process during a fact finding call by the Minister of Public Service to the institute, explained that the vaccine trials which is at its final stages, has been designed to control the three economically important ticks namely the Brown ear ticks, the Blue ticks and the Bont ticks.
The scientists hosted Minister Muruli Mukasa who came to see what Naro, scientists are developing in the various Institutes in a bid to increase their salaries because many are leaving the country in search of green pasture.
The minister said there is already a policy in place for salary increment to the scientists but promised to follow this up to avoid brain drain because the products developed by the scientists are of great importance to the people of the country in terms of food security.
Dr Kabi explained that ticks generally suck host blood and transmit several diseases resulting into anaemia, death, poor growth and poor weight gain and diminished productivity.
The diseases they transmit have continuously constrained Ugandan farmers from keeping improved livestock let alone improve their local cattle breeds for higher milk yields due to the high susceptibility to diseases.
He notes that Uganda currently losses up to Shs3.8 trillion annually in revenue due to cattle deaths, poor growth, costs of diseases control, destruction of non-target organisms such as bees, dung beetles and birds which act as tourist attraction.
There has been an increased use of chemical acaricides and antibiotics by farmers due to acaricide resistance and increased prevalence of tick-borne disease respectively.
The anti-tick vaccine will disable tick feeding on animals, its reproduction, disease transmission and its moulting behaviour to disable its growth. To curb this there is need for farmers to adopt the vaccine.
Once released farmers and veterinary doctors will administer it either through intramuscular injection or by swallowing it orally.
Progress
The on-station trials have been very successful with positive results and Naro is now in the process of engaging the Uganda National Council for Science and Technology and National Drug Authority (NDA) to grant permission for On-farm trials which will be carried out throughout the different agricultural zones of the country.
Once the trials are completed it will be registered by the NDA before commercial production commences.
The vaccine will is of great importance to farmers because it will reduce the frequency of acaricide application thus saving profits and also enable cattle upgrades for higher productivity.
Farmers will greatly benefit from reduced disease incidences resulting from ticks and tick-borne diseases.
In addition, the use of the vaccine will lead to reduced environmental hazard, beef and milk contamination which occur due to the current excessive acaricide application.
Tick-borne diseases
There are a number of tick-borne disease and they include, Babesiosis or tick fever which is a feverish disease of domestic and wild animals leading to anemia and haemoglobinuria which can be fatal. This is transmitted by blue tick.
Bovine anaplasmosis, which is also transmitted by the blue tick, is an infectious, noncontagious haemotropic disease of cattle characterised in the acute form by fever, anaemia, weakness, constipation, yellowing of the mucous membranes, lack of appetite, depression, dehydration, and laboured breathing.
Animals surviving an acute attack often make a slow recovery, resulting in losses in milk or meat production
Others are East Coast fever a cattle disease caused by the protozoan parasite transmitted by brown ear tick and heart water and dermatophilosis transmitted by bont tick
Development process
Paul Kasaija, a Phd student, who is involved in developing the anti-tick vaccine explains that at the laboratory level the scientists’ study the different stages of tick growth namely egg, nymph and adult.
They identify molecules in the gene of the ticks and carry out gene silencing of the molecule which enables the ticks to transmit diseases and these are knocked out.
Once these molecules are removed from the ticks, the effect of disease transfer to the animals will be silenced.
The genes which command the reproduction of the ticks once knocked out will also enable the ticks not to reproduce. The entire laboratory process is through genetic modification of the tick genes. The purpose is to surpress reproduction of the ticks and the feeding behaviour of sucking blood from animals.
Once the genes are engineered, it is used to formulate the vaccine and according to Kasaija, it has been tested on exotic animals and indigenous ones at the institute and the team has observed that it is working effectively.
This means once the animals are vaccinated, the anti-vaccine will cause immune response on the animals and when the tick comes to suck blood from the animal, the antibiotics will affect its feeding habit by weakening it.
Its reproduction is also affected in that once the female ones lay eggs, they will not hatch and this will control their population while some will end up dying after sucking blood from the vaccinated animal.
Tick-borne diseases
East Coast Fever
Anaplasmosis
Babesiosis
Heartwater
