Effect of Age and Sex on the Acquisition of Immunity to Toxoplasmosis in Cats*

Abstract

The effects of age and sex of the cat on oocyst shedding, multiplication of Toxoplasma gondii in tissues of cats, and acquisition of immunity were investigated after oral inoculation of cats with Toxoplasma cysts. Twenty-five cats varying in age from 1 week to 39 months were killed 7-97 days after inoculation with T. gondii. Homogenates of brain, heart, mesenteric lymph nodes, retina, and blood from these cats were inoculated into mice to test for Toxoplasma infectivity. Toxoplasma was isolated more frequently and in higher titers in mice receiving inocula from cats of the youngest age group (1 week old). Toxoplasma gondii was isolated from tissues of only 2 of 21 cats older than 2 months (at the time of inoculation), although all of the animals shed oocysts within 1 week after ingesting the parasites. The number of oocysts shed varied among littermates of the same sex and between sexes. Generally, cats younger than 12 months shed more oocysts than older cats. The number of oocysts shed by older cats varied considerably; males generally shed more oocysts than the females. However, the numbers of cats examined were too small for statistical comparison. Nevertheless, the observations suggest that cats older than 12 months should not be used in experiments where numbers of oocysts shed is critical.

Antibodies to Toxoplasma gondii and Leishmania spp. in domestic cats from Luanda, Angola

“…Nevertheless, seroprevalence of infection in domestic cats has been found to vary with their lifestyle (wild, stray or domestic), age, serological test used and geographical location (Gauss et al, 2003). Cats of all ages, gender and breeds are susceptible to infection (Dubey et al, 1977;Dorny et al, 2002). In the present study, the odds of a cat being seropositive increased by an average factor of 1.58 for each 1-year increase in age.…”

Seroprevalence of Toxoplasma gondii infection in feral cats in Qatar

“…Cat bioassays have not provided any clear evidence of sex-bias in the occurrence of toxoplasmosis [19]. However, experimental studies in mice have shown that females are more susceptible than males to T. gondii infection and develop more severe cerebral inflammation.…”

Testosterone‐unresponsiveness of existing immunity against Plasmodium chabaudi malaria

“…The male sex hormone testosterone (Te) is known to promote a wide variety of diseases including different forms of cancer such as prostate-and hepatocarcinoma (Henderson et al 1982, Kemp, Leary & Drinkwater 1989 as well as to aggravate the course and outcome of infectious diseases by parasites (Alexander & Stimson 1988). Indeed, there is vast literature available that Te increases the susceptibility of vertebrate hosts towards many different protozoan parasites (Kierszenbaum et al , Dubey, Hoover & Walls 1977, Greenblatt & Rosenstreich 1984 and helminthic endoparasites (Dow & Jarrett 1960, Dobson 1962, Miller 1965, Ohbayashi & Sakamoto 1966, Charniga et al 1981, Bone & Bottjer 1986. Te even increases the susceptibility towards arthropod ectoparasites such as ticks (Ali & Sweatman 1966).…”