Cat Parasites, a Zoonotic Aspect

Parasites are present everywhere and known to harm humans and a variety of wild, domestic, and pet animals. They impose both direct and indirect damages and affect the production potential.

By Prof Dr Abdullah G Arijo

Cats are largely adopted pen animals and are exposed to endo and ectoparasites. Virtually all parasite groups including helminth and protozoans as endo-parasites and fleas, ticks, and mites as ectoparasites infect/infest, respectively.
In the usually hot and humid climate of the tropics, bacterial, contagious, and vector-borne diseases of humans and animals flourish more than cold season. Numerous states in such regions of the world remain elusive with insufficient resources at their disposal to tackle the immense challenges of disease endured by their population groups effectively. Priority has been granted to veterinary disease research, surveillance, and control only if these diseases influence the alleviation of poverty or if they pose a potential zoonotic danger to the population.

However, in some communities, in Asia, economic development and growing affluence have resulted in shifting attitudes towards domestic animal ownership, resulting in increasing standards and demands on veterinary surgeons for better canine and feline medicine and surgery knowledge. However, amid the extension of access to information technologies, geographical information concerning epidemiology is important to veterinarians.

At any time in their lives, cats are vulnerable to infection with parasites. They can hamper the health of a pet if left undetected and untreated, from merely being annoying to having a range of life-threatening disorders. Some parasites, with children being a highly vulnerable subject, can also infect and spread the disease to humans! Parasites do not discriminate; there is a danger of both indoor and outdoor dogs.
Endo-parasitic infections are known as one of the major problems in animals as well as humans. However, in cats endoparasites may be found all over the internal body that may include blood parasites, gastrointestinal parasites, liver parasites, etc. parasitic infections lead to economic losses or even death.
There may also be a vast range of species of parasites that infect your pet, from single-celled protozoa to more complex kinds of bacteria. While different infection mechanisms occur, most of these parasitic blood infections are spread by ticks and fleas.

Ticks, fleas, and mosquitoes are spread worldwide, and they are granted considerable medical importance by their ability to transmit pathogens. On the other hand, the increasing success of pets in developing countries especially cat animals with their independent lifestyle contributes to an increased risk of human interaction with feline ectoparasites (Dantas et al., 2014). Information on the species of ticks infesting cats and vector-borne pathogens (VBPs) concealed by them is limited (Otranto et al., 2010).

Parasitic pathogens spread by blood-sucking arthropod bites are caused by vector-borne diseases (mainly mosquitos and ticks). Over the last few years, novel viruses have arisen, or old ones have re-emerged, typically with improvements in their pervasiveness/prevalence of disease (i.e., pervasiveness/prevalence, geographical distribution, and pathogenicity). The pervasiveness/prevalence of such vector-borne pet diseases, such as canine granulocytic Anaplasmosis, Babesiosis, Thrombolytic Anaplasmosis, canine monocytic Ehrlichiosis and Leishmaniosis, is growing in Europe (Beugnet et al., 2009). These illnesses are spread by ticks.

Gastrointestinal parasitism, with a high prevalence rate of up to 45 % in some populations, is a common issue in cats. These parasites may be protozoan creatures that are wormlike or unicellular. Non-specific symptoms are typically induced, such as a rough coat, diarrhea, coughing, vomiting, lack of appetite, mucous or bloody faeces, pale mucous membranes, or potty appearance. A cat may be weakened by vomiting, diarrhea, anaemia, and dehydration caused by intestinal parasites, rendering it more vulnerable to infectious, bacterial, and other infections. Importantly, certain cats’ GI parasites will infect humans as well.

The most important feline gastrointestinal pathogens are T. gondii and T. cati, among the zoonotic agents transmitted by animals as described by Robertson and Thompson 2002. Also, the cat acts as a reservoir for L. infantum in some countries such as Southern Europe and Iran (Hatam et al., 2010). In cats, too several non-zoonotic infectious agents are essential. Diarrhoea and otitis are caused by parasites including Isospora and Otodectes bacteria.

There was no difference in the severity of infection among the gender (male/female). Associated with parasitic infection the risk factor age of cat was shown to be significant. Six months of age (younger cats) are more likely than older ones. Based on the above data, it is assumed that infection is likely to occur at any age, either by eggs or larval-containing tissue, although the highest frequency of infection occurs in kittens and young cats (Lorcain, 1994).
The gastrointestinal parasites present in cats that are reported belong to 2 major groups, namely, protozoans and helminths. The Helminths reported to be found in cats are roundworms (Toxoscaris leonine and Toxocaracati), hookworms (Ancylostoma and Uncinaria), tapeworms (cestodes), whipworms and stomach worms. The Protozoans reported to be found in cats are Isospor, Giardia and Toxoplasma.

Household cats are a possible source of multiple agents for infectious diseases; however, many of these diseases are managed by routine medical treatment, proper vaccine regimens and parasite chemotherapy in cats belonging to responsible owners. To control these illnesses, free-roaming cats also lack the requisite preventive treatment and as a result pose a possible health danger to other household animals, wildlife, and humans.

Two major classes of endoparasites are split into protozoa and helminths (worms). Protozoa are single-celled parasites containing multiple species that cause serious diseases, such as toxoplasmosis, leishmaniasis, isosporiasis, giardiasis and babesiosis in cats and dogs. The intestines are home to roundworms, hookworm (A. caninum) and whipworm (T. vulpis). Others are extra-intestinal and live in the cardiorespiratory system, such as D. itis, A. abstrusus and A. vasorum. In dogs and cats, the two most common worm species are roundworm and tapeworm. Few parasites are widely considered to be present, such as the Toxocara type, which can infect dogs and cats in the UK. While there is no rise in the pervasiveness/prevalence of Toxocara, the genus still poses a high zoonotic risk.
Cats can be easily infested in blood, intestinal as well as extra-intestinal parasites due to their scavenging or hunting nature, as at times the prey or the body they feed on can be infested with protozoal or parasitic infection or infestation which may transfer to the cat through oral route or vectors like ticks, mosquitos, etc.

Some protozoan and helminth parasites are easily transmitted to humans due to close contact with a pet cat, therefore is a dire need to adopt care in cat handling. Available literature showed that 25.8% of human beings were infected with T. gondii in Pakistan. The prevalence was 20.64% in males and 26.82% in the female. This is associated with risk in women.

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