A E.U., H R.S., O M.
boophilus, hyalomma, infestation, nigeria, rhipicephalus, ticks
A E.U., H R.S., O M.. Tick infestation of dogs in Makurdi metropolis, Benue State-Nigeria. The Internet Journal of Veterinary Medicine. 2009 Volume 7 Number 2.
This study was conducted to identify tick species infesting domestic dogs, to compare the infestation rates between free roaming and kenneled dogs in Makurdi, capital of Benue State-Nigeria and to find out the predilection sites of attachment of tick species on dogs. A total of 72 (55.38%) dogs were infested with different species of ticks out of the 130 dogs examined. Using stereoscopic observation and standard taxonomic keys, 533 nymphs and adult ticks were identified with distribution as follows:
Ticks are arthropods belonging to the class Arachnida, which are generally obligate and temporary ectoparasites of vertebrates, feeding on blood and tissue fluids of their hosts. They are the second most important group next to insects of arthropod vectors of diseases transmissible to animals and human beings. Tickborne diseases commonly transmitted to human beings include Lyme disease, Ehrlichiosis, Babesiosis, Rocky Mountain spotted fever, Colorado tick fever, Tularaemia, Q fever, Tick paralysis, Spotted fever and Tick encephalitis. Ticks can be considered as zoonotic risk because, not only can they be found outdoors, but also in homes, where they may come in contact with human beings while searching for favourable environmental conditions to subsist 1,2,3. Knowing the possible link between dog ectoparasite and the transmission of zoonosis, this study became necessary in view of the recent trends observed on the increased number of free roaming and kenneled dogs in Makurdi. The increased number of dogs has been related to the increasing security problems in the metropolitan. Dogs are employed as watch agents in many households. Studies on the prevalence of ticks in dogs in Makurdi is scarce, there are no available epidemiological information on ticks and disease transmission. The present study was aimed at identifying the tick species infesting domestic dogs and to compare the infestation rates between free-roaming and kenneled dogs and preferred sites of attachment of tick species found on dogs in Makurdi metropolis.
Materials and Methods
The study was carried out between June and August 2005 in Makurdi, capital of Benue State-Nigeria. The area is located on latitude 7º 44’ N and longitude 8º 35’ E. and defined by a 26 km radius with the Benue River and its tributaries covering a substantial area of the town. Makurdi located at the heart land of the tropical guinea savanna zone of central Nigeria has an annual average rainfall of 1090 mm. There are two distinct seasons, the rainy season and the dry season; the former lasts from April to October and the latter from November to March. Makurdi has a temperature range between a minimum of 27.8ºC to 28.2ºC and a maximum of 30.1ºC to 34.1ºC (Meteolorgical Department, Nigerian Air Force Base Makurdi, Unpub. Data) The town is divided into zones: North Bank, Wurukum, High Level, Low level, Wadata, Fiidi ward and Ankpa ward mainly inhabited by civil servant, paramilitary, soldiers, traders, fishermen, farmers and craftsmen.
The specimens were collected by the researchers from residential houses in Makurdi metropolis following standard procedures4. A total of 130 randomly selected dogs were examined, all the selected dogs were examined for ticks on the face, ears, neck, belly, back and limbs (interdigital spaces) and the number of ticks per region were recorded. Dogs on which at least one tick was found were considered positive.
Ticks collected were preserved in 70% alcohol and sent to the Advanced Biology Laboratory of the University of Agriculture Makurdi for examination under stereomicroscope and identification using standard taxonomic keys 4.
Prevalence values within each factor (location, tick species, months, and predilection sites of ticks on dogs) were compared by chi-squared test at P<0.05,significance level.
Table 1 shows the prevalence of tick infestation in dogs in the selected areas in Makurdi. Out of 130 dogs examined, 72(55.4%) were infested with ticks. North Bank and Wurukum recorded the highest infestation rate with 84.6% and 55.4% respectively. The least infestation rate was observed at High Level, 27.7%. No significant difference was observed between the different locations and the prevalence of tick infestation (X2 = 5.32, P>0.05).
A total of 533 nymphs and adults ticks were collected with the following infestation rate:
The comparison of tick infestation in free roaming and kenneled dogs is shown in Table 3. It was observed that out of 108 free roaming dogs, 64(59.6%) were found infested with the three species of ticks while of the 22 kenneled dogs only 8(7.4%) were found infested but with only two species of ticks;
The monthly variation and prevalence of tick species is shown in Table 4. The highest number of ticks was recorded during the months of June (54.1%) followed by 25.0% in August and 20.8% in July.
Table 5 shows the pattern of single and multiple tick infestation in dogs in Makurdi. 28 (38.8%) of dogs were found infested with the three species of ticks (
The results of this study indicated that there was a relatively high prevalence of tick infestation in dogs in Makurdi. North-Bank and Wurukum which are known as slums had the highest number of infested dogs. These areas are densely populated mainly by farmers, fishermen, petty traders and craftsmen who keep dogs without proper care. The poor environmental sanitation prevailing in these areas, the common sights of garbage dumps where dogs frequently source for food and the presence of other susceptible animals (cattle, goats and sheep) in the communities could be major factors contributing to the survival and propagation of these ticks. The low prevalence of tick infestation observed in dogs at High Level could be attributed to the level of care and confinement of dogs by the owners.
The ears and interdigital spaces of limbs were found to be the most predilection sites for ticks on dogs in the study area. The presence of ticks in these sites could be probably due to their exposure to the questing ticks as the dogs roam about. Preference for the ears and interdigital spaces have been earlier reported on dogs in the USA and Mexico 5,6. These areas are hiding places for the ticks and are less accessible to the dog to remove them by its paws compared with locations such as the neck or the face. This also agrees with a previous report showing the ears and interdigital spaces as preferred sites of the ticks on dogs7. The low infestation observed on the head and the belly could be probably due to the exposure of these parts to environmental factors, or the fact that the ticks are often more easily seen and removed by the dog owners. Similar reasons proffered for association of ticks and locations above are likely responsible for the significant observation between kenneled dogs (10.9%) and free roaming dogs (89.1%). This is because free roaming dogs are most common in North Bank and Wurukum; it is also possible that as these free roaming dogs were taken along to farm or for hunting they were further exposed. The free roaming dogs are owned by people who may not take dog bath seriously, the ticks therefore find suitable environment to aggregate and multiply on the dogs hence their abundance on the free roaming dogs. This high rate of infestation in the free roaming dogs agrees with an earlier study conducted in Jos, Plateau State-Nigeria 8. The infestation observed in the kenneled dogs could be as a result of their release and interaction with free roaming dogs at night. It is also possible for these dogs to become infested from the household compounds. On the other hand, the low rate of infestation observed in the kenneled dogs in the study area may be due to their degree of restriction which shields them from infestation, also owners of kenneled dogs are better income earners that would care to bath the dogs and take them for clinics when necessary. Moreover, these dogs are closer to their owners who always care for them by removing any visible tick. This shows that in the study area, habitat and restriction are strong factors on tick infestation in dogs.
Variations in the observations of the monthly reports of tick on dogs in this study could be due to the climatic or ecological conditions. The highest rate of infestation recorded during the rainy month of June could be the result of the relatively high humidity, temperature and greenish environment observed in the area. The drastic decline in tick infestation during the month of July could be attributed to a short break of rainfall observed which lead to a reduced humidity and increase in temperature. Most engorged female ticks are known to drop off their hosts during the dry season when climatic conditions like temperature rises to the highest peak (34ºC). Subsequently, they move into shelters, such as crevices in floors, walls, and shutters where they deposit enormous number of eggs which stop development until the onset of rains characterized with suitable moisture and decrease in temperature thus favouring the hatching of eggs. Earlier observations in Nigeria and other parts of the world have shown that peak population of ticks always related with climatic conditions of the area studied9,10,11,12.
Although infestations with a single species of tick were recorded, most of the dogs examined had mixed infection with different tick species. A similar trend of tick infestation has been observed by different workers13,14. However, variation in the rates of prevalence between single and mixed infestation exists, this could be attributed to the exposure of the dogs or their innate resistance to some species of ticks15. The total absence of
The authors are grateful to the owners of dogs for the help rendered during collection of ticks.