Anthrax is a zoonotic disease which usually affects agricultural workers, animal handlers, veterinarians and industrial laborers working with animal products (bone meal, hides and wool)(1). In this perspective the incidence and prevalence of anthrax in child-ren, especially, infants is exceedingly rare. Here, we present a case of cutaneous anthrax, in an infant with unusual epidemiologic features.

A 10-month-old female infant came to us with a painless ulcerated lesion over the right buttock of 10 days duration. The infant’s mother initially noticed a papule in that area that increased in size and ulcerated spon-taneously to form a blackish eschar. The only other significant history was the death of a cattle in the neighborhood. Cutaneous examination revealed a dark hemorrhagic eschar surrounded by a zone of edema and erythema, studded with several small vesicles that have coalesced (Fig. 1). There was no regional lymphadenopathy. The systemic examination was normal. Hematological and biochemical parameters were within normal limits. Gram stain of the smear taken from the base of eschar showed large, encapsulated Gram positive bacilli in short chains. Culture and identification was done by standard microbiological procedures. Bacillus anthracis and Staphylococcus aureus were isolated. The patient was put on injection crystalline penicillin 200,000 units intravenously four hourly. Inspite of the treatment, the lesion progressed to eschar formation. The full course of treatment was given for 14 days. Subsequently, the patient had an uneventful recovery.

Fig. 1. Gluteal region showing typical black eschar, misnomered earlier as "malignant pustule".

Anthrax is often a fatal bacterial infection that occurs when Bacillus anthracis endospores enter the body through abrasions in the skin or by inhalation or ingestion(2). It is a zoonosis to which most mammals, especially grazing herbivores are considered susceptible. Human infections result from contact with contaminated animals or animal products and there are no cases of human to human transmission. Human anthrax is not common. Cutaneous anthrax, the most common form, is usually curable. It begins as painless, pruritic papule that appears at the site of inoculation within 3 to 10 days. Several days later, a vesicle or ring of vesicles develop along with enlargement of original lesion to 4 to 6 cm. The lesion ulcerates and a central eschar is formed which remains in situ for up to 3 weeks. Painful regional lymphadenopathy may occur and it may persist long after successful treatment with penicillin. On the other hand, the early clinical diagnosis of inhalational anthrax and intestinal anthrax is often difficult. The outcome of these forms of the disease is usually fatal.

A few sporadic cases and outbreaks of anthrax have occurred in India(3). The incidence of anthrax in animals and in man throughout India is not known accurately due to the fact that a large number of cases go unreported and only a fraction of human cases receive medical attention in a hospital. Detailed information collected for the three southern states – Andhra Pradesh, Karnataka, and Tamil Nadu have confirmed the endemicity of anthrax. During the last two decades, about 70 cases of human anthrax have been encountered at Christian Medical College, Vellore, of which there have been 26 cases of cutaneous anthrax(4). A review of Indian scenario in 1996, has found 112 cases of anthrax reported in places other than Vellore(3). Majority of these cases were of cutaneous anthrax numbering seventy one. There were 11 cases of meningitis, 9 patients with gastrointestinal anthrax, one patient had septicemia following cutaneous anthrax. In one series, 20 patients with internal anthrax including intestinal, septicemic, meningeal and pulmonary forms were described. In an epidemiological study from Gambia, no relationship was found between death and the age of the patient or the site or number of the lesions of cutaneous anthrax(5).

Anthrax in infants is exceedingly rare. Earlier, we had reported 20 cases of anthrax over a period of 10 years but none of them was an infant(6). Heyworth et al.(5) in an epi-demiologic study of an outbreak of anthrax from Gambia reported only 0.45% (2/448) cases of cutaneous anthrax among infants. The patients were of the age of 2 months and 10 months respectively (both males). The mode of transmission was related to the habit of sharing communal loofahs (made of fibers taken from the Rhum palm) amongst people in the local community. It was responsible for human to human transmission which is said to be rare.

The lesion which is most commonly confused with cutaneous anthrax (malignant pustule) is vaccinia which no longer exists. Milkers nodules contracted from the teats of the cow, are characterized by one or several brownish red dome shaped smooth surfaced or slightly, papillomatous vegetations (resemble pyogenic granulomas) which are generally confined to the hands and forearms(7). Orf (ecthyma contagiosum) is a skin disease found usually in slaughters or shepherds who may be in contact with sheep suffering from ecthyma contagiosum(8). It is caused by a virus and the appearance is more ragged and angry looking compared to the malignant pustule of anthrax Moreover, Orf lacks the characteristic central eschar. Malignant pustule can be confused with a boil. However, a Gram stained smear of the exudate from the lesion usually shows the bacilli if the case is anthrax. A painful pustular eschar in a febrile patient indicates a secondary infection, most often with Staphylococcus or Streptococcus. The isolation of Staphylococcus aureus in our case could be a secondary invader.

In the absence of concrete evidence, the mode of transmission in this case can only be conjectured. Various forms of evidence strongly suggest that flies play a role in the transmission of B. anthracis to humans and domestic animals during an anthrax outbreak (9). This evidence includes the cutaneous cases associated with insect bites in both Zimbabwe and India, the demonstrated ability of several species of Hematophagous diptera to transmit B. anthracis mechanically for at least 4 hours after contact with an infected animal and the ability of other diptera to contaminate surfaces with B.anthracis either with spores in their faeces or by direct contamination with spores or vegetative forms on their body surfaces(9).

Funding: None.
Competing interests: None stated.