Severe anthrax outbreaks in Italy in 2004: considerations on factors involved in the spread of infection.

This research explores a severe anthrax outbreak in Southern Italy during the summer of 2004. It delves into the factors that could have been involved in spreading the disease, such as insects transmitting the spores and favourable weather conditions.

Background

• The study focuses on an anthrax outbreak that took place in the Basilicata region of Southern Italy in 2004. Anthrax is a disease caused by the Bacillus anthracis bacterium, affecting both humans and animals.
• The disease is usually sporadic in Italy, but during the summer of 2004, it spread rapidly among several animal species in a large area in Basilicata, where anthrax prevalence is low and vaccination had been halted since 1998.

The Outbreak

• Over a span of 41 days, several animals succumbed to the disease: 81 cattle, 15 sheep, 9 goats, 11 horses, and 8 deer. This represents a highly significant mortality rate and spread of the disease.

Genetic Analysis

• To understand the source and spread of the disease, the research team used Multiple-locus Variable-Number Tandem Repeats Analysis (MLVA) and Single Nucleotide Repeats (SNRs) Analysis on 53 isolates from the infected animals.
• MLVA showed that all isolates belonged to Cluster Ala, genotype 1, indicating they originated from the same source.
• SNRs Analysis revealed that 48 out of the 53 B. anthracis strains belonged to a single clonal lineage, the sub-genotype sgt – eB. There were also two sporadic mutants (sgt – eB,m1 and sgt – eB,m2)

Factors in Spreading the Infection

• The study also aimed to identify the potential reasons for the rapid and widespread infection. Two main hypotheses were explored: the role of insect vectors in transmitting anthrax spores, and the potential influence of favourable weather conditions.
• The research did not provide definitive answers, suggesting further study into these factors.