Vector borne and protozoan disease treatment and control in cattle

23/05/2023

Tsetse-transmitted Trypanosomiasis
Tsetse-transmitted trypanosomiasis refers to a group of diseases caused by protozoa of the genus Trypanosoma and affects all domesticated animals. The major veterinary species are T congolense, T vivax, T brucei brucei, and T simiae. T brucei rhodesiense and T brucei gambiense are zoonotic, with people as the predominant host. For the animals mainly affected by these tsetse-transmitted trypanosomes and the geographic areas where tsetse-transmitted trypanosomiasis occurs, see Table: Tsetse-transmitted Trypanosomes.

10/09/2022

Theileria annulata, a protozoan parasite of cattle and domestic buffaloes, is transmitted by ticks of the genus Hyalomma, and causes a disease named Mediterranean or tropical theileriosis. In this research 50 cattle naturally infected with Theileria annulata were treated with the extract of the plant Peganum harmala. The treatment was continued for 5 days, the dose of the extract being 5 mg/kg per day. After the treatment, 39 cattle responded to the treatment and recovered, but 11 did not respond to the treatment and died. The recovery rate of animals treated with the extract of the plant Peganum harmala was 78%.

10/09/2022

Theileriosis (a protozoan disease)
Young exotic and crossbred cattle are highly susceptible. Indian breeds of cattle (Zebu) are comparatively resistant.
Buffaloes are also infected but symptoms are mild.
Fever, swollen peripheral lymph nodes, pallour of mucous membranes, anaemia, nasal discharge, jaundice, salivation, rapid and shallow breathing , watery eyes etc are common symptoms.
Cattle lose condition rapidly.
Some animals show nervous signs characterized by stepping gait, head pressing, recumbency, unconsciousness and death.
PREVENTION AND TREATMENT
Regular tick control is the most effective way to keep these infections in check (see chapter on tick control).
Seek veterinary treatment if above symptoms of any of the above diseases are seen, since treatment is most effective in the initial stages. Delays may result in death.
For control of theileriosis, vaccinate all exotic and crossbred animals aged 3 months and above, once in a lifetime .

10/09/2022

Trypanosomosis is a widely spread protozoan disease complex which affects cattle and other wide range of hosts in sub-Saharan Africa. The course of the disease may run from a chronic long lasting to an acute and rapidly fatal depending on the vector-parasite-host interactions. The disease is mainly characterized by intermittent fever, progressive anaemia, and loss of condition of susceptible hosts which if untreated leads to heavy mortalities The etiological agent of the disease is unicellular flagellated protozoan parasite of a genus Trypanosoma. Trypanosomes are blood borne unicellular protozoan parasites dwelling in various body and tissue fluids. The parasite is known for more than a century, but still control of the disease remains elusive
Several species of hematophagous tsetse flies of the genus Glossina are the vectors of African trypanosomosis and are responsible for cyclical transmission of the parasitic protozoan between numerous vertebrate hosts. The vector is distributed over wide range of habitats covering about 10 million square kilometers of potential grazing lands in 37 countries which are rendered unsuitable for livestock breeding and farming across the African content, exposing 160 million cattle to the risk of anaemia, emaciation, and death and 55 million people to the risk of fatal sleep. As a result agriculture revolution which is a key element in the fight against poverty and the improvement of food security in developing countries failed in tsetse infested areas of sub-Saharan Africa
In Ethiopia, trypanosomosis is one of the most important diseases that limit livestock productivity and agricultural development due to its high prevalence in the most arable and fertile land of southwest and northwest part of the country following the greater river basins of Abay, Omo, Ghibe, and Baro [6]. Currently about 220,000 km2 areas of the above-mentioned regions are infested with five species of tsetse flies, namely, Glossina pallidipes, G. morsitans, G. fuscipes, G. tachinoides, and G. longipennis. More than 10 million heads of cattle in Ethiopia are at risk of variable degrees of trypanosomosis at any time of the year, of which six million are tsetse borne. A number of studies have been so far undertaken in different parts of the country to determine the magnitude of this economically important disease Nevertheless, there are no published studies which assess the prevalence of this disease in Dale Wabera district.
The distribution of trypanosomes is dynamic due to climatic change, ecological disturbances, and human interventions. Some tsetse infested areas are scarce in infrastructure and devoid of human settlements. In such areas sufficient information is lacking about the status of trypanosomosis. Even in already studied areas updating the prevalence and status of the disease have paramount importance for understanding the epidemiology of the disease, to facilitate the choice of suitable control methods, and to help in planning for development programs in the area. Therefore, the objectives of this study were to determine the prevalence of bovine trypanosomosis in Dale Wabera district and to evaluate association of bovine trypanosomosis with anaemia.

10/09/2022

The endemic vector-borne diseases transmitted by tsetse and ticks impose heavy burdens on the livestock keepers in Africa. Applying deltamethrin to the belly, legs, and ears of cattle offers a possibility of mitigating these losses at a cost affordable to livestock keepers. Although studies have quantified the impacts of individual diseases on livestock productivity, little is known about the dual economic benefits of controlling both tsetse and ticks, nor about the number of cattle that need to be treated to confer these benefits. Alongside an epidemiological study in south-east Uganda, a farm level assessment was done to investigate the benefits and costs of spraying different proportions of the village cattle population using this restricted application protocol.

10/09/2022

African trypanosomiasis in cattle represents a major constraint to agricultural and socio-economic development in vast areas of Africa. The disease is caused principally by three species of trypanosome (Trypanosoma congolense, T. vivax and T. brucei) which are transmitted by several species of tsetse flies (Glossina). Trypanosomiasis in cattle results in poor productivity and mortality. The widespread nature of the disease is due to the distribution of tsetse, the ability of the trypanosomes to escape host defense mechanisms by undergoing antigenic variation and by their capacity to infect a large variety of other hosts, including wild game. Cattle can also act as carriers of the human pathogen T. b. rhodesiense. Following the intradermal inoculation of trypanosomes by the tsetse fly into a susceptible host, there is proliferation of trypanosomes within the skin resulting in a localized skin reaction, known as the chancre, which develops before the appearance of parasites in the bloodstream.

10/09/2022

Transmission and Epidemiology of Trypanosomiasis in Animals
Most tsetse transmission is cyclic and begins when blood from a trypanosome-infected animal is ingested by the fly. The trypanosome alters its surface coat, multiplies in the fly, then alters its surface coat again, and becomes infective. T brucei spp migrate within the tsetse from the gut and eventually to the salivary glands; the cycle for T congolense stops at the hypopharynx, and the salivary glands are not invaded; the entire cycle for T vivax occurs in the proboscis. Therefore, the location within the tsetse can be useful in identifying the parasite species. The animal-infective form in the tsetse salivary gland is referred to as the metacyclic form. The life cycle in the tsetse may be as short as 1 week with T vivax or extend to a few weeks for T brucei spp.
Tsetse flies (genus Glossina) are restricted to Africa from about latitude 15°N to 29°S. The 3 main species inhabit relatively distinct environments: G morsitans usually is found in savanna country, G palpalis prefers areas around rivers and lakes, and G fusca lives in high forest areas. All 3 species transmit trypanosomes, and all feed on various mammals.
Mechanical transmission can occur through tsetse or other biting flies. In the case of T vivax, Tabanus spp and other biting flies seem to be the primary mechanical vectors outside tsetse-endemic areas, as in Central and South America. Mechanical transmission requires only that blood containing infectious trypanosomes be transferred by bite from one animal to another.

10/09/2022

Prevention and treatment of trypanosomiasis in cattle
At present no vaccine is available.
If detected early, Trypanosomosis can be treated with trypanocidal drugs for therapeutic and prophylactic purposes.
Therapeutic drugs for cattle include diminazene aceturate, homidium chloride and homidium bromide. Prophylactic drugs for cattle include homidium chloride, homidium bromide and isometamidium.
However the effectiveness of these drugs is now questionable following years of use, causing resistence and now variuos strains of Trypanosomosis to occur.
Another area of control that has been studied is to eradicate the tsetse flies which transmit the disease.
The most common of the procedures that have been deveoped are: spraying insecticide on tsetse habitat, destruction of tsetse habitat and alteration of vegetation so that it becomes unsuitable for tsetse flies.
However, these methods are costly and require a high level of management, organisation and specialist expertise.

10/09/2022

Trypanosomosis is usually transmitted through blood lymph and other fluids of infected animals. It is caused by Flagellated protozoan parasites that live in the fluids and tissue of its host animal.
Often the disease is transmitted through the bite of an infected tsetse fly which has been feeding on an infected animal.
Symptoms
Symptoms often begin to show four to 24 days after infection. The most important clinical sign is nonregenerative anaemia.
The major clinical signs are:
intermittent fever
anaemia
oedema
lacrimation
enlarged lymph nodes
abortion
decreased fertility
loss of appetite, body condition and productivity
early death in acute forms
emaciation and eventual death in chronic forms often after digestive and/or nervous signs

10/09/2022

Trypanosomosis/ Sleeping Disease/ 'Nagana'
Mainly occuring in Africa, Trypanosomosis, or Sleeping Disease, is a infection affecting both animals and humans.
The disease mainly occurs in areas where Tsetse flies inhabit. Tsetse flies infest 10 million square kilometres and affect 37 countries, mostly in Africa, where it is known as ‘Nagana’.
It is the most economically important livestock disease of Africa, as it can have a devastating impact on rural areas.

19/08/2022

Two bulls in a South Dakota beef cattle herd have tested positive for bovine trichomoniasis, also known as trich, a disease that can be economically devastating to cattle producers.
The South Dakota Animal Industry Board (AIB) announced on May 30 that the bulls had been detected in Oglala Lakota County after testing positive for the disease. Officials from AIB are working with the owner of the cattle and the local veterinarian to develop a management plan to control the disease. Neighboring cattle ranchers will also be notified so that potential contact with infected animals does not occur.
Trich is a protozoal parasite that is transmitted from cows and bulls during breeding. Bred females that contract Trichomonas foetus can result in early term abortions.
There are no physical signs of the disease. However, a cattle producer might become aware that they have trich when a high number of females are open (not pregnant) or late calving.
To prevent having trich in a cattle herd, producers can buy virgin bulls for breeding and run them on a clean herd of females. If purchasing non-virgin bulls it is recommend that they be tested for trich prior to breeding. Bulls already in the herd can also be tested to determine if there is trich present in the herd.
Routine pregnancy checking and selling of open females is also recommended to reduce the spread. Maintaining good border fences on pasture is another way to reduce the risk of cattle commingling that might have trich.
The AIB has implemented the following rules for South Dakota in cooperation with cattle producers to reduce the spread of trich:
Non-virgin bulls must be tested negative for trich prior to being sold, loaned or leased in South Dakota for breeding purposes;
Any non-virgin bull entering South Dakota must be tested negative for trich;
Non-virgin, non-pregnant female cattle (open cows) may not be imported, loaned, leased nor acquired for breeding purposes in South Dakota.

10/06/2022