What is babesiosis (pyroplasmosis)? Where do ixodid ticks live?
Dog babesiosis (pyroplasmosis) is a natural focal protozoal non-contagious blood-parasitic disease that occurs acutely or chronically, caused by the simplest parasite Babesia (Piroplasma) canis and manifests itself in high fever, anemia and yellowness of the mucous membranes, and heart and intestines.
This disease has been known since 1895 when G.P. Piana and B. Galli-Valerio reported that the disease, known as “bile fever” or “malignant jaundice of hunting dogs,” was caused by blood parasite, which they named Piroplasma bigeminum (canis variant). Later, this parasite was given the name Babesia canis.
In Russia, the causative agent of Babesia canis was first discovered in 1909 by V.L. Yakimov in St. Petersburg at a dog brought from the North Caucasus and V.L. Lyubinetskiy, who observed the pathogen in Kiev. In Belarus, N.I. pointed to parasitism of pyroplasm (babesia) in dogs Dylko (1977).
The carrier of babesia are ixodid ticks of the genus Dermacentor. Many researchers have noted transvarial transmission of ticks by the pathogen of babesiosis by ticks, and if we take into account that wild carnivorous canine families are also susceptible to infection with B. canis, they can therefore also serve as natural reservoirs.
In the last two decades, there has been a sharp change in the dynamics of tick resettlement. Indeed, while in the 1960s and 1980s, cases of ixodid attacks on dogs were recorded, with rare exceptions, in rural areas and suburbs (in the country, hunting, etc.), in 2005-2013 the vast majority of tick attacks occurred on territories of the cities themselves (in parks, squares, and even in the yards).
The conditions and habitat of ixodid ticks in the city differ significantly from those in natural biotopes. The following features can be distinguished here: increased atmospheric gas contamination and reduced oxygen concentration, pronounced fragmentation of tick habitats, significant variety of local climatic conditions, insignificant species diversity of hosts (dogs, cats, synanthropic rodents), frequent changes in the living environment associated with building and reconstruction of buildings, high density of people and transport, their active movement. These conditions undoubtedly affect the occurrence and maintenance of hot spots in the city limits.
The entire territory of any modern city can be divided into the old, young part, and new buildings.
The old part of the city is a building site of more than 50 years ago. It is characterized by a high degree of urbanization, significant gas contamination and a small amount of vegetation. As a rule, such a zone is practically free of ticks. The main factor in their skidding and moving is host animals, most often dogs. Within the zone, ticks can live in parks, squares and courtyards where there are bushes.
Young areas - after their development, 5 to 50 years have passed. They are characterized by a sufficient formation of the landscape, and urbanization in these territories is lower than in the first zone (in recent decades, when building new areas, more green spaces are projected immediately). During the formation of the landscape, centers of congestion have time to form. The zone can be divided into two subzones:
- areas where ticks were absent
- territories where ticks used to be.
In the subzones where ixodids were absent, the formation of foci of ticking, as a rule, is a long process. Ticks are introduced from outside by host animals. Then, getting on the plants, the fed females lay eggs, from which the larvae hatch. If they find hosts for themselves, a new hotbed of congestion is gradually forming.
Subzones, where ticks used to be, are sites in young areas where construction has not been carried out. These may be existing parks, squares and forest belts, which it was decided to maintain. Hot spots in such subzones are preserved, and then ticks settle in neighboring territories.
For these reasons, the burdening of young areas can be significant.
New buildings are areas where construction is currently underway and up to 5 years after it. Construction work is currently greatly changing the natural landscape, which most often leads to the death of ticks. Therefore, the settlement of this territory with ticks occurs gradually (simultaneously with the formation of a new landscape) by introduction of animal-feeding animals or during their natural migration from bordering zaklechivannye zones. In general, new buildings are characterized by the absence of ticks or a very low ticking.