SUBACUTE ANTHRAX IN CATTLE IN MADRAS
By G. R. VISWANATHAN, G.M.V.C., Veterinary Investigation Officer (Madras) and S. VENKATRAMA
AYYAR, G.M.V.C., Assistant to the Veterinary Investigation Officer, Madras
(Received for publication on 2 April 1945)
A NTHRAX is sporadic in Madras, occurring all over the province and at all times of the year in
an acute form. In any one outbreak, it is rare for more than one or two animals to be
affected. The onset is sudden and ends fatally without symptoms being seen. This paper concerns
anthrax in bovines, especially in cattle belonging to the Corporation of Madras. In this outbreak
many animals were affected and most of them suffered from a subacute form of the disease.
Hutyra and Marek [1938] state that outbreaks of subacute cases of anthrax do occur. In Central
Provinces, Bachan Singh [1938] recorded an outbreak of anthrax of subacute type, which occurred in
Raipur. Viswanathan [1938 and 1942] recorded similar type of outbreaks in bovines at Villupuram
Taluk of South Arcot, Madagasira Taluk of Anantapur, and in Tiruvellore Taluk of Chingleput. Thus
in village M. thirteen animals were affected, of which five died and eight recovered ; in village S. thirty-
three animals were affected, of which thirtytwo died and one recovered.
These outbreaks also were confirmed as anthrax by examination of blood smears.
HISTORY OF PRESENT OUTBREAK
This occurred in epizootic form in June, 1944, reaching its maximum about the fourth
week. Two animals were found dead on the morning of June 18. Blood smears were positive for
anthrax. On the same day, anthrax serum was used at the rate of 15 c.c. for the healthy and 40
to 60 c.c., according to the size, for the ailing animals. Sixtyfour healthy and five ailing animals
were treated.
These animals were stationed at A. Depot of the Madras Corporation, which for the past two
months had been used as a foot and mouth disease segregation camp. A and B Depot animals before
they were segregated here were in the habit of going to the dumping ground, where street refuse and
rubbish are deposited and where dead animals are usually buried. Of the five animals treated on
June 18, two were found dead of anthrax two days later. On June 20, the other three animals were
given intravenously 20 c.c. of antianthrax serum. On June 21, two animals were found dead of
anthrax, one of them being a treated animal and the other a newly purchased one.
Before the actual investigation began on June 21, six animals had died of anthrax, diagnosed
by examination of blood smears.
THE PRESENT INVESTIGATION
On June 20, when the outbreak was first reported, it was decided to vaccinate with anthrax
spore vaccine. During the previous years, six cases of anthrax had occurred in Corporation animals.
During the month before the present outbreak, there had been an outbreak of foot and mouth
disease and this appeared to be a predisposing cause, as many of the animals were weak and debi-
litated and also had wounds between the digits. Moreover, as stated, these animals were in the
habit of going to a dumping ground, where previous anthrax cases and other animals had been buried.
Further due to careless handling and disposal of carcases, it is possible that the water tub and food
stuffs may have been contaminated. It is also possible, that biting flies such as Tabanus may have
transmitted the infection.
On June 21, the temperature of all the animals in the Depot were taken before vaccination,
in order to detect the ones in the incubation stage. Fifteen animals were then showing high tem-
perature. Of these, 11 belonged to the B. Depot and 4 to the A. Depot.
Period of incubation. According to Gaiger and Davis [1938] the period of incubation is 24 hours
to 2 or 3 days or may even be as long as 14 days. From the details collected in this outbreak, five
animals have shown a period of incubation of 12 hours, but this was probably not correct for the
first two deaths, as they were not observed probably till the disease was confirmed as anthrax on
232