most people infected with m .tuberculosis do not develop active disease. in healthy individuals, the lifetime risk of developing infection to disease is 5-10%. reactivation of tb often occurs in older children and adolescent and is more common in patients who acquire tb at age 7 years and older. pulmonary tuberculosis may manifest in several forms, including endobronchial tb with focal lymphade...

zika virus is an arbovirus identified first time in 1947 in uganda. zika epidemic is a threat far greater than the ebola outbreak. the world health organization has urged asian countries to be vigilant about the risk of spreading zika virus and preventive measures to control it. in iran, 64 species of mosquitoes from culicidea family have been reported three of which belong to the aedes genus, ...

The evolution of virulence was studied in a virus subjected to alternating episodes of vertical and horizontal transmission. Bacteriophage f1 was used as the parasite because it establishes a debilitating but non-fatal infection that can be transmitted vertically (from a host to its progeny) as well as horizontally (infection of new hosts). Horizontal transmission was required of all phage at s...

We investigate host-pathogen dynamics and conditions for coexistence in two models incorporating frequency-dependent horizontal transmission in conjunction with vertical transmission. The first model combines frequency-dependent and uniparental vertical transmission, while the second addresses parasites transmitted vertically via both parents. For the first model, we ask how the addition of ver...