ECHO-11 as a respiratory virus: quantitation of infection in man

Abstract

A B S T R A C T Through a series of controlled experiments in volunteers, quantitative aspects of infection, illness, and immunity to ECHO-11 virus were studied. ECHO-11 is a transmissable viral infection in man and equally infectious to the upper respiratory and the intestinal tracts. The rate of infection was directly related to the dose of virus exposure, but any infectious dose of virus produced illness in only about one-third of the infected subjects. The infectious dose for man varied over a billionfold range. Larger challenge doses caused no difference in the local symptoms at the portal of entry or in the peak severity of illness, but symptoms were more diverse and prolonged after a higher dose. Persons with asymptomatic infections became just as heavily infected as ill persons.In respiratory secretions from natural infection, the titer of infectious virus was found to be about 102 median infective doses in tissue culture (TCID50)/ml. At this level, up to 40% of exposed contacts could be infected per milliliter of secretion.The observed rate of spread was 24%. This lowdose inoculum caused illness in 12%o' of volunteers

Bronchoalveolar lavage fluid cellularity and soluble intercellular adhesion molecule-1 in children with colds

“…Study Groups I and II do not represent the whole clinical spectrum of coryzal illness, and the prevalence of lower airway viral infection and inflammation with coryzal symptoms cannot be estimated from our study. However, infection of the lower respiratory tract must occur in at least a proportion of children with trivial colds, since the viruses isolated from BALF were identical to those isolated from nasal samples during community-acquired coryzal illness, 14,15 and the spectrum of respiratory symptoms was similar to that reported for adults with viral colds. 2 Could the BALF viral isolates be due to contamination from infected upper respiratory tract secretions?…”

Virus Antibody Survey in Different European Populations Indicates Risk Association Between Coxsackievirus B1 and Type 1 Diabetes

“…Furthermore, neutralizing antibodies are biologically active because they neutralize the infectivity of the virus and correlate with immune protection against that EV serotype. On some occasions, however, the neutralizing antibody response can remain low and even be transient, especially if the infection is caused by a low dose of the virus (24). Therefore, the prevalence of neutralizing antibodies in this kind of cross-sectional retrospective survey may underestimate the true number of past infections, making it difficult to assess the proportion of diabetes cases that could be causally linked to CVBs.…”

Minimum Infective Dose of the Major Human Respiratory and Enteric Viruses Transmitted Through Food and the Environment

“…Virus titers in throat swabs and fecal specimens of infected volunteers were 8.0 9 10 1 -6.3 9 10 2 TCID 50 and 1.2 9 10 3 -8.0 9 10 3 TCID 50 , respectively (Buckland et al 1959). Saliba et al (1968) reported the infectivity of echovirus type 11 in man by experimentally infecting healthy adult volunteers with either high (10 6 TCID 50 ) or low (10 2 , 10 3 , and 10 4 TCID 50 ) doses of the virus. The volunteers had varying levels of antibody titers against echovirus 11 including some with 1:20 or greater.…”

“…Outbreaks of disease caused by echoviruses demonstrate their ability to cause significant morbidity and mortality world-wide (Hill 1996) especially among infants and children (Arnon et al 1991;Krous et al 1973;Ventura et al 2001). A number of studies reported experimental infection with echoviruses in animals (Pindak and Clapper 1965;Vasilenko et al 1967;Vasilenko and Atsev 1965) and few used human volunteers (Buckland et al 1959;Kasel et al 1965b;Philipson 1958;Saliba et al 1968;Schiff et al 1984b).…”