Amplification of tick‐borne encephalitis virus infection during co‐feeding of ticks

Abstract

Following engorgement of Rhipicephalus appendiculatus larvae on guinea-pigs infected with tick-borne encephalitis (TBE) virus, none of the engorged larvae or emergent nymphs contained detectable infectious virus. However, one of twelve pools, each containing three of the unfed nymphs, was positive when screened by polymerase chain reaction (PCR), indicating a low prevalence of TBE virus infection in the unfed nymphs. After engorgement of the nymphs on four uninfected guinea-pigs, 19/24 (79%) fed nymphs from one guinea-pig and 4/25 (16%) fed nymphs from a second guinea-pig were infected; all the ticks examined from the other two guinea-pigs were uninfected. The results suggest that TBE virus was transmitted from a low proportion of infected nymphs (infected as larvae) to uninfected nymphs as they fed together on an uninfected guinea-pig. Such amplification of the initial infection, at the population level, could play an important role in maintaining TBE virus infections in nature, particularly if there is a low level of vertical transmission from one tick generation to the next.

Trends in tick population dynamics and pathogen transmission in emerging tick-borne pathogens in Europe: an introduction

“…The dynamics of TBE has been studied extensively in the last decades (Amicizia et al 2013;Jaenson et al 2012). The importance of co-feeding for the transmission cycle has been highlighted (Labuda et al 1993;, and has also been modelled (Hartemink et al 2008). Climatic factors, such as rapid spring warming has been linked to the distribution of TBE , but cannot explain the whole spatio-temporal pattern (Š umilo et al 2007).…”

The Role of Game (Wild Boar and Roe Deer) in the Spread of Tick-Borne Encephalitis in the Czech Republic

“…Furthermore, co-feeding should also be considered as a possible route of infection (Labuda et al 1993a, b, c, Randolph et al 1996. Game can disseminate ticks infected also to relatively distant areas.…”

Kyasanur Forest Disease: a Status Update

“…Wide spread distribution of this species of tick in forests especially tropical and deciduous of southern and central India. KFDV has been isolated from various other species of ticks, H. turturis, H pauana kinneari, H. kyasanurensis, H. minuta, Dermacentor, Ixodes, Ornithodorus (adult), Hyalomma marginatum isaaci (Verma et al, 1960;Singh et al, 1964;Singh and Bhatt., 1968;Bhat and Naik, 1978;Bhat et al, 1978a In the transmission of KFDV, human act as a dead end host, with no sufficient viremia for further transmission (Labuda et al, 1993). Neutralizing antibodies of KFDV have been found in cattle, buffaloes, goats, wild boars, porcupines, squirrels, flying squirrels, rats, mice, shrews, bats (Bhatt et al, 1978b) and a number of bird species.…”

“…Man having no role in virus transmission in any of these diseases. Humans do not develop adequate viremia to infect the ticks (Labuda et al, 1993). In KFD small mammals, mainly rodents have been considered as the reservoir.…”