Seroprevalence and risk factor analysis of Toxoplasma gondii Among Stray and Domesticated Dogs (Canis familiaris) in Antipolo and Metro Manila


Lowell Reich M. Guy and Gil M. Penuliar*

Institute of Biology, University of the Philippines,
Diliman, Quezon City 1101, Philippines
*Medical Microbiology Laboratory, Institute of Biology,
University of the Philippines, Diliman, Quezon City, Philippines

corresponding author: This email address is being protected from spambots. You need JavaScript enabled to view it.



Toxoplasma gondii is a protozoan parasite that causes toxoplasmosis. It infects a variety of warm-blooded animals, due to its low level of host specificity, and can cause miscarriage and other birth problems. In the Philippines, the seroprevalence of the parasite among dogs is unknown. To fill this research gap, the objectives of the study were to determine the seroprevalence of T. gondii among stray and domesticated dogs in Antipolo and Metro Manila and the risk factors involved in transmission. From the 158 blood samples collected, 24 were seropositive for T. gondii and the overall seroprevalence was 15.2%. Seropositivity was higher among strays (26.9%) compared to domesticated dogs (8.3%). Most of the risk factors analyzed had no direct correlation with T. gondii seropositivity, but animal welfare was found to have significant association with parasite transmission among stray dogs (OR = 4.041 95% CI 1.494-10.931, P=0.006).



Toxoplasma gondii is a protozoan parasite known to cause toxoplasmosis among warm-blooded animals. It was first discovered in a rodent by Nicolle and Manceaux in 1908, who named it after its structure and host. T. gondii is an intracellular apicomplexan capable of replicating within any nucleated mammalian or avian cell. Felines are the definitive host, while all warm-blooded animals, including dogs, serve as intermediate hosts (Dubey et al. 1998). Its life cycle consists of three infectious forms that contribute to its proliferation and survival: (a) bradyzoites that encyst in neural and muscular tissues, (b) oocysts, shed in cat feces, that sporulate into sporozoites, while (c) tachyzoites that invade the body through the blood and lymph vessels (Petersen and Dubey 2005). . . . . read more