MINI REVIEW article Front. Vet. Sc, 26 February 2019 Sec. Parasitology
Toxoplasmosis is caused by the globally distributed protozoan parasite Toxoplasma gondii (phylum Apicomplexa); the disease can be clinically important for almost all homeothermic animals, including birds and humans. Toxoplasmosis course involves general clinical signs, such as fever, anorexia, or dyspnea, and more specific signs with neural, respiratory, cutaneous, or ocular involvement. Because of the wide range of clinical signs, the diagnosis in domestic and pet animals can be complicated. Hence, this review aims to provide a comprehensive analysis of some scarcely discussed aspects of toxoplasmosis, such as ocular and cutaneous manifestations, congenital infections, influence of T. gondii genotype on clinical toxoplasmosis, and recent findings regarding differential diagnosis. This review could be of special interest to clinicians and researchers.
Toxoplasmosis is caused by the globally distributed intracellular protozoan parasite Toxoplasma gondii (phylum Apicomplexa, family Sarcocystidae). The disease has a complex epidemiology; the parasite is capable of infecting virtually all warm-blooded animals, and has a two-host life cycle (1). Domestic cats and other felids are the definitive hosts (DHs). All non-feline animals, including dogs and humans, are intermediate hosts (IHs), however, T. gondii can also undergo asexual reproduction in Felidae that act as IHs. There are three stages in the protozoans life cycle that explain its biological success. First, tachyzoites multiply actively in tissues, quickly spread to almost all organs, and cause most of the pathology. Once they reach specific tissues (central nervous system, muscle, and viscera), they convert into bradyzoites which remain latent in a cyst form leading to a life-long chronic infection until a DH ingests the tissue. Then, bradyzoites are released and penetrate the small intestine epithelial cells, giving rise to schizonts that form gamonts and, finally, oocysts. Oocysts constitute the environmentally resistant (and infective) stage. Hosts can become infected horizontally by ingesting tissues containing cysts, consuming water or food contaminated with oocysts, or by transfusion or transplantation with parasitized organs. They can also result infected vertically, by congenital infection.
In general, T. gondii infection is associated with a low rate of morbidity and mortality in dogs and cats, but clinical consequences for primary care clinics should be taken into account. Clinical toxoplasmosis is more frequent in cats than in dogs, which commonly suffer from neosporosis by Neospora caninum, and among them, non-vaccinated animals are more susceptible.
On review of the available literature (www.ncbi.nlm.nih.gov), ~79 clinical cases in cats and 45 in dogs have been comprehensively reported after 1989, when N. caninum was newly described causing toxoplasmosis-like disease in dogs (1). Numerous studies have shown seroprevalence and/or parasite prevalence ranges in dogs and cats from 6 to 88% worldwide [reviewed in reference (1)]. Seroprevalence status in cats is essential regarding zoonosis prevention and has been recently reviewed elsewhere (2).
Other review papers have focused on toxoplasmosis diagnosis and treatment. In the present article, the authors aimed to highlight less known clinical manifestations, to review aspects regarding differential diagnosis, and to determine how strain/genotype may be involved in the clinical presentation of the disease, which could be of special interest for clinicians and researchers.
Can You Get Toxoplasmosis From Your Dog?
Toxoplasmosis is considered a zoonotic disease, which means it can be passed from animals to humans. However, dogs are not primary hosts, and they do not shed T. gondii in their feces, so you dont have to worry about contracting it from them. The parasite is most often passed to humans by one of these methods:
Toxoplasmosis is not typically a concern for healthy adults, but it can cause flu-like symptoms for people with weakened immune systems. Its also highly problematic for pregnant women.
The Centers for Disease Control and Prevention (CDC) estimates that 40 million people in the United States may be infected with T. gondii, but most wont show any symptoms.
Toxoplasmosis is a serious issue for pregnant women since the organism can cross the placenta and cause severe congenital disabilities. Newborns exposed to T. gondii can have jaundice, enlarged organs, intellectual disabilities, impaired eyesight, and seizures. Some may die a short time after birth.
Pregnant women are typically advised not to clean up pet waste to help avoid contracting Toxoplasmosis or other parasitic diseases.
There are things you can do to help keep you and your dog safe from toxoplasmosis, such as:
If your dog does need treatment for toxoplasmosis, pet insurance can help cover the costs of treatment. Dig into pet insurance to learn how it can help you care for your best friend.
The information presented in this article is for educational and informational purposes only and does not constitute or substitute for the advice of your veterinarian.
Causes of Toxoplasmosis
Dogs contract toxoplasmosis by ingesting one of the following items infected with T. gondii eggs:
The disease replicates by cloning, then it migrates from the GI system and spreads throughout a dogs body. The replicated clones cluster together, forming cysts that lodge various tissues and organs.
An infected dog cannot spread the parasite through its stool.
Can Dogs Get Toxoplasmosis? | Wag!
2Program of Masters in Animal Medicine and Welfare, Faculty of Veterinary Medicine, University of Santo Amaro, São Paulo, Brazil
Toxoplasmosis is caused by the globally distributed protozoan parasite Toxoplasma gondii (phylum Apicomplexa); the disease can be clinically important for almost all homeothermic animals, including birds and humans. Toxoplasmosis course involves general clinical signs, such as fever, anorexia, or dyspnea, and more specific signs with neural, respiratory, cutaneous, or ocular involvement. Because of the wide range of clinical signs, the diagnosis in domestic and pet animals can be complicated. Hence, this review aims to provide a comprehensive analysis of some scarcely discussed aspects of toxoplasmosis, such as ocular and cutaneous manifestations, congenital infections, influence of T. gondii genotype on clinical toxoplasmosis, and recent findings regarding differential diagnosis. This review could be of special interest to clinicians and researchers.
Toxoplasmosis is caused by the globally distributed intracellular protozoan parasite Toxoplasma gondii (phylum Apicomplexa, family Sarcocystidae). The disease has a complex epidemiology; the parasite is capable of infecting virtually all warm-blooded animals, and has a two-host life cycle (1). Domestic cats and other felids are the definitive hosts (DHs). All non-feline animals, including dogs and humans, are intermediate hosts (IHs), however, T. gondii can also undergo asexual reproduction in Felidae that act as IHs. There are three stages in the protozoans life cycle that explain its biological success. First, tachyzoites multiply actively in tissues, quickly spread to almost all organs, and cause most of the pathology. Once they reach specific tissues (central nervous system, muscle, and viscera), they convert into bradyzoites which remain latent in a cyst form leading to a life-long chronic infection until a DH ingests the tissue. Then, bradyzoites are released and penetrate the small intestine epithelial cells, giving rise to schizonts that form gamonts and, finally, oocysts. Oocysts constitute the environmentally resistant (and infective) stage. Hosts can become infected horizontally by ingesting tissues containing cysts, consuming water or food contaminated with oocysts, or by transfusion or transplantation with parasitized organs. They can also result infected vertically, by congenital infection.
In general, T. gondii infection is associated with a low rate of morbidity and mortality in dogs and cats, but clinical consequences for primary care clinics should be taken into account. Clinical toxoplasmosis is more frequent in cats than in dogs, which commonly suffer from neosporosis by Neospora caninum, and among them, non-vaccinated animals are more susceptible.
On review of the available literature (www.ncbi.nlm.nih.gov), ~79 clinical cases in cats and 45 in dogs have been comprehensively reported after 1989, when N. caninum was newly described causing toxoplasmosis-like disease in dogs (1). Numerous studies have shown seroprevalence and/or parasite prevalence ranges in dogs and cats from 6 to 88% worldwide [reviewed in reference (1)]. Seroprevalence status in cats is essential regarding zoonosis prevention and has been recently reviewed elsewhere (2).
Other review papers have focused on toxoplasmosis diagnosis and treatment. In the present article, the authors aimed to highlight less known clinical manifestations, to review aspects regarding differential diagnosis, and to determine how strain/genotype may be involved in the clinical presentation of the disease, which could be of special interest for clinicians and researchers.