A murine model to study Toxoplasma gondii and a Secondary Influenza A Virus Infection -

Abstract

Toxoplasma gondii is an obligate intracellular protozoan parasite that can infect a wide variety of animals, including one third of the human worldwide population. It causes a- to mild symptomatic disease in immunocompetent patients but may become fatal in immunocompromised patients and in fetus of primo-infected pregnant women. Influenza A virus (H1N1) is a negative-sense single stranded RNA virus belonging the Orthomyxoviridae family. Influenza A viruses (IAV) is a significant cause of morbidity and mortality in human population worldwide. Influenza A-H1N1 virus emerging from pigs caused a pandemic in 2009 and continues to cause infections worldwide. Like other flu causing viruses, H1N1 causes the typical flu symptoms including: sore throat, cough, fever, chills and some body aches. AN infection with influenza virus may also lead to complications such as pneumonia and cardiac complications. As both T. gondii and IAV infections are common, and since the risk of infection with either pathogen is extremely high, it is intriguing to investigate the outcome of secondary infection with IAV following a pre-existing acute T. gondii infection. To the best of our knowledge, no study investigated the outcome of a pre-existing acute T. gondii infection followed by a secondary infection with IAV. We used 6-8 week old female BALB-c mice which were intraperitoneally injected with type II T. gondii parasites, followed by IAV intranasal inoculation. Mice were sacrificed at days 3 and 5 post infection with IAV, and those either infected with T. gondii infected with both T. gondii and IAV were verified for acute toxoplasmosis by Western Blot. Parasitic and viral loads in mice organs were quantified by quantitative Real-Time PCR. We have shown that 10percent of mice infected with IAV alone and 10percent of those infected with T. gondii alone die by day 22. Interestingly, an infection with T. gondii followed by IAV the next day has shown 60percent mortality by day 22, while an infection with T. gondii followed by IAV 4 days later has shown 40percent