Published Date: 2012-05-07 22:48:11
Subject: PRO/AH/EDR> Anthrax, bovine - Argentina (05): (BA)
Archive Number: 20120507.1125538
ANTHRAX, BOVINE - ARGENTINA (05): (BUENOS AIRES)
A ProMED-mail post
ProMED-mail is a program of the
International Society for Infectious Diseases
Date: Sat 5 May 2012
From: Ramon Noseda <firstname.lastname@example.org> [edited]
80 adult cattle have died on a cattle breeding estancia [ranch] in Dolores partido [2nd level administrative division]. The problem started in the 1st half of April  with the acute deaths of a number of animals. Through a clinical error it was diagnosed as enterotoxaemia due to a clostridial infection and the stock were vaccinated. When the deaths continued, a 2nd veterinarian was called in, who submitted a metacarpal bone to the laboratory for analysis. [This is the standard protocol for suspected anthrax in Argentina. - Mod.MHJ] The presence of _Bacillus anthracis_ was confirmed and the livestock were vaccinated with Sterne. For a while deaths continued but there have been no further deaths in the past 2 weeks. The estancia had not vaccinated their 700 livestock for a number of years. The Dolores partido is in the Anthrax Surveillance area in the Province of Buenos Aires and its last anthrax outbreak had been in 2005.
CEO/Laboratorio Azul Diagnostico SA
Av 25 de Mayo 479
(B 7300 FXE) Azul Bs As
[Mortality rates of 10 percent or higher in double digits from anthrax are unusual to say the least. And this case nicely points up the need to consider treating exposed animals that may be incubating disease with a long acting antibiotic as soon as possible, as Sterne vaccine takes a minimum of 8 days before it provides any protection. You should either treat and then wait 7-10 days before vaccinating as it is a live vaccine, or others argue to give vaccine with antibiotics as enough Sterne spores survive the antibiotics to start successfully germinating from around day 5 to 6 to begin to provide longer protection. This reduces the cost as the animals are handled only once.
Such a heavy mortality is characteristic of a massive exposure to female tabanid biting-flies, which while snacking carry infection from beast to beast on their shearing mouthparts. While anthrax cases had not been 'seen' in this district for some 6 years normal sporadic cases from contaminated grazing can occur for some years and with flies be turned from an occasional 'silent' death into an epidemic. The only way to persuade ranchers that there is a risk is to make sure that any unexpected acute death is sampled and checked. Then any positive can be used to persuade the neighbouring ranches to get their fingers out and vaccinate, and each following spring for the next 3-5 years. - Mod.MHJ]
[For the HealthMap/ProMED map showing the location of Partido de Dolores, Buenos Aires province, Argentina, see http://healthmap.org/r/2jQZ.- Mod.MPP]