The Australian Sentinel Practices Research Network, 1 January to 31 March 2017.

The Australian Sentinel Practices Research Network was established in 1991 to provide a rapid, national, monitoring scheme for infectious diseases that can alert public health officials of epidemics before they arise. The network consists of general practitioners, throughout all 8 states and territories in Australia, who report presentations on a number of defined medical conditions each week. This report presents data from the 1st quarter of 2017 (1 January to 31 March) and includes the syndromic surveillance of influenza-like-illness, gastroenteritis, chicken pox, and shingles, and the virological surveillance of respiratory viruses including influenza A, influenza B, RSV and rhinovirus.

The failure of R0.

The basic reproductive ratio, R(0), is one of the fundamental concepts in mathematical biology. It is a threshold parameter, intended to quantify the spread of disease by estimating the average number of secondary infections in a wholly susceptible population, giving an indication of the invasion strength of an epidemic: if R(0) < 1, the disease dies out, whereas if R(0) > 1, the disease persists. R(0) has been widely used as a measure of disease strength to estimate the effectiveness of control measures and to form the backbone of disease-management policy. However, in almost every aspect that matters, R(0) is flawed. Diseases can persist with R(0) < 1, while diseases with R(0) > 1 can die out. We show that the same model of malaria gives many different values of R(0), depending on the method used, with the sole common property that they have a threshold at 1. We also survey estimated values of R(0) for a variety of diseases, and examine some of the alternatives that have been proposed. If R(0) is to be used, it must be accompanied by caveats about the method of calculation, underlying model assumptions and evidence that it is actually a threshold. Otherwise, the concept is meaningless.