Bebesiosis is an emerging zoonotic disease caused by entraerythrocytic parasites of Babesia genus that is spread by ticks, which may also be transmitted through blood transfusion.
By Arzoo Ashraf
Babesiosis is among the most frequent illnesses in free-living livestock globally, with cattle, rodents and carnivores being the most susceptible upto 60%. Investigation in infected region detect B. microti was the predominant species in people infected with Babesiosis and it has increase public-health threat. Tick-borne illnesses are most common between April and October, when the weather is warmer and ticks are more active, as well as when people spend more time in tick-infested regions.
Epidemiology
In United State (136cases in New York between 1970 to 1991 and 160cases between 1969 and 1998) are reported with 3-8% prevalence. Only 29 cases reported with 42% mortality of infection in Europe. All babesial pathogens and those strongly linked to the genus Theileria are spread by ixodid ticks via blood transfusion and reproduce in the vertebrate host’s red blood cells, which are referred to as Prioplasms because of their pear shape. Ixodes ricinus, the tick that transmits B. divergens to humans, has a three-year life cycle, with larvae in the first year, nymphs in the second, and adults in the third. Ixodes ricinus is also the vector for the Lyme disease spirochete in Europe. Due to temperature elevation ticks become more active, cause a high incidence of B divergens infections, so there will be more chance of infection in those people who frequently closed to cattle.
Vector lifecycle and transmission
Members of the Ixodidae family are the only proven vectors of Babesia parasites, and their function in B. microti transmission has been thoroughly established. To grow to the next stage, both the larva and nymph stages require a blood meal from their rodent hosts, while adults typically feed on deer as a permanent food supply. Recently hatched larval stages eat a blood meal from their vertebrate host at the end of the summer, which is when they first pick up parasites if the host is infected. During the winter, when the ticks are dormant, the parasites pass through the intestinal epithelium and migrate to the salivary glands, where they moult into nymph stages. In order for these parasites to form active sporozoites once the ticks feed again, they need some activation from warm-blooded hosts. In order to prepare for their transformation into adults, the nymph stages must eat again the next summer, enabling them to spread parasites into the vertebrate host. The zoonotic infection of the human host occurs at this stage of tick maturation.
Clinical presentation
Complications are more likely in immune compromised patients and the main clinical manifestation of babesiosis is linked with anemia with hypotension, headache, chills, fever, fatigue, night sweats, weight loss, nausea, myalgia, disseminated intravascular coagulation, altered mental status, hemolytic toxins, renal insufficiency, respiratory distress syndrome and inflammatory mediators produced during infection. Incubation period varies from 1 to 6 weeks and may be long as 3 months while clinically apparent cases fall in range from 50-60years.The mechanism of infectious diseases is directly outcome of ability of parasites to infiltrate host’s red blood cells and infection persist asymptomatic mainly in younger or immune competent individuals while in immunocomproised individuals risk of disease remains high..
Diagnosis
Babesiasis spp are apicomplexan parasites transmit occurs through vector bite to animals (Cattle and sheep), known as Tick Borne diseases. Sample is collected as 2.5 ml of peripheral blood sample within Ethylene Diamine Tetra Acetate (EDTA) tube. Thick and thin blood smear is investigated by Giemsa’s stained blood method (GMS) microscopy and diagnosed through Polymerase Chain reaction (PCR). After air dry, methanol fixation with 10% Giemsa’s is done and identified based on characteristic morphology.
Molecular Identification and confirmation
Blood protozoan DNA is extracted using a commercially available kit (Invitrogen Purelink Genomic DNA mini kit) from blood sample through chloroform method.PCR is carried out in a final reaction volume of 25μl in the thin walled PCR tubes to amplify genomic DNA of Babesia and Theileria species. In blood smear microscopy, prevalence of Tick Borne Protozoan disease is significantly varied on area, season and breed of Cattle and Sheep.
Treatment
The lack of knowledge of bebesiosis in the medical community, non-specific symptoms, and the lack of simple and efficient quick diagnostic tests are all major issues with bebesiosis management.Convenient, wellevaluated diagnostic techniques, such as serological testing or molecular biology assays, for detecting such diseases quickly and reliably. Clindamycin and quinine are used in conjunction in severe situations. However, there is a high risk of antimicrobial and drug-related toxicity with this regimen.
Prevention
Tick repellents should be used before visiting a tick-infested region, and skin should be thoroughly examined following exposure. As there is no availability of vaccine for Babesiosis, prophylactic antibiotic treatment is not suggested. Protective techniques, such as wearing appropriate clothes, using insect sprays containing DEET, and removing attached ticks as soon as they are discovered, are the best mechanism to decrease bite risk.
Authors:
- Aarzoo Ashraf, M.Phil. Epidemiology and Public health, University of Agriculture, Faisalabad.
- Muhammad Sohail Sajid, Associate professor, Dept. of Parasitology, University of Agriculture, Faisalabad.
- Kashif Hussain, PhD Parasitology, University of agriculture, Faisalabad.