Parasitic diseases of the heart II: Toxoplasmosis and other protozoan and helminthic diseases

CYSTICERCOSIS & HEART: A systematic review

Cysticercosis is a parasitic tissue infection caused by larval cysts of the tapeworm Taenia solium. These larval cysts infect brain, muscle, or other tissue, and are a major cause of adult-onset seizures in most low-income countries with tropical climate. Prevalence it's around 50 million people. Although cardiovascular system is not the most affected, this disease can also be associated with multiple and randomly distributed cysts in the subpericardium, subendocardium and myocardium in up to 25% of infected patients. Most cardiac cysticercosis' cases are asymptomatic, but it can manifest with ventricular arrhythmias and conduction disorders. Area Covered: The "Neglected Tropical Diseases and other Infectious Diseases affecting the Heart" (NET-Heart project) is an initiative by the Emerging Leaders group of the Interamerican Society of Cardiology to systematically review all these endemic conditions affecting the heart. A systematic review was conducted following PRISMA guidelines and including articles published in MEDLINE, ScienceDirect, PubMed and LILACS databases. A total of 41 papers were included in this review. Expert Opinion: In the areas of greatest prevalence, unhealthiness and poverty favor the development of this disease, which highlights the need to establish global health policies that reduce morbidity and mortality, economic losses of the affected population, and health costs related to hospitalizations for cardiovascular involvement. Authors provide an algorithm to evaluate the possibility of Cysticercosis' cardiovascular complications.

Toxoplasma gondii: from animals to humans

Toxoplasmosis is one of the more common parasitic zoonoses world-wide. Its causative agent, Toxoplasma gondii, is a facultatively heteroxenous, polyxenous protozoon that has developed several potential routes of transmission within and between different host species. If first contracted during pregnancy, T. gondii may be transmitted vertically by tachyzoites that are passed to the foetus via the placenta. Horizontal transmission of T. gondii may involve three life-cycle stages, i.e. ingesting infectious oocysts from the environment or ingesting tissue cysts or tachyzoites which are contained in meat or primary offal (viscera) of many different animals. Transmission may also occur via tachyzoites contained in blood products, tissue transplants, or unpasteurised milk. However, it is not known which of these routes is more important epidemiologically. In the past, the consumption of raw or undercooked meat, in particular of pigs and sheep, has been regarded as a major route of transmission to humans. However, recent studies showed that the prevalence of T. gondii in meat-producing animals decreased considerably over the past 20 years in areas with intensive farm management. For example, in several countries of the European Union prevalences of T. gondii in fattening pigs are now <1%. Considering these data it is unlikely that pork is still a major source of infection for humans in these countries. However, it is likely that the major routes of transmission are different in human populations with differences in culture and eating habits. In the Americas, recent outbreaks of acute toxoplasmosis in humans have been associated with oocyst contamination of the environment. Therefore, future epidemiological studies on T. gondii infections should consider the role of oocysts as potential sources of infection for humans, and methods to monitor these are currently being developed. This review presents recent epidemiological data on T. gondii, hypotheses on the major routes of transmission to humans in different populations, and preventive measures that may reduce the risk of contracting a primary infection during pregnancy.