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KARACHI, Oct 26: Pakistan’s first clinically confirmed anthrax case has occurred in Karachi.
Though the government and the hospital concerned officially denied having received any “positive” case, this has come as the first confirmed case in the country.
According to highly reliable sources, the patient is at present admitted to the Aga Khan University Hospital where his pathological examination has shown that he has contracted the deadly disease.
According to the sources, the patient is on most effective antibiotics such as ciprofloxin, penicillin, cephalosporins, tetracycline and fluoroquinolone.
The sources said the patient had inhaled anthrax organisms in the powder shape once he opened an envelope in an office.
Since there already existed awareness among people about the disease once it began to make headlines in the US and other western countries, the entire office staff, including the one who opened the envelope, went on heavy intake of antibiotics.
Speaking about the patient, the sources said that spores remained dormant in the lungs and had not so far gone into germinating and initiating systemic infection stage.
“This is mainly because of those precautions that the patient has not so far developed a high level of toxins in his body,” a senior expert, who is not directly associated with this case, said.
According to him, once high-levels of toxin are produced by anthrax bacilli in the body, antibiotic therapy becomes ineffective. He advised the public, particularly general physicians, that antibiotic therapy should also be used for prophylaxis in asymptomatic patients with suspected exposure to anthrax spore aerosol and said: “Prolonged treatment is needed to allow time for clearance or inactivation of spores deposited in the lungs, as spores are not affected by antibiotics”.
On the management aspect of the disease, he said that patient isolation was not required and there were no quarantine requirements.
He added that dressings, discharges from lesions, other contaminated materials and cadavers should be disinfected, preferably by incineration or cremation or by deep burial with quicklime.
According to him, sterilization may also be achieved by autoclaving, washing with chemicals which include aqueous formaldehyde, glutaraldehyde, hypchlorite, hydrogen peroxide or peracetic acid or by fumigation with ethylene oxide of formaldehyde vapour.
A study carried out by Dawn by contacting as many as 13 medical sources across the world has shown that anthrax is mainly a disease of mammals, most commonly encountered in grazing animals. Until the introduction and widespread use of modern veterinary vaccines, it was a major cause of fatal disease in cattle, sheep, goats, camels, horses and pigs.
According to these sources, anthrax continues to be reported in many countries in domesticated as well as wild herbivores, especially where livestock vaccination programmes are inadequate or have been disrupted. “Human anthrax, acquired from diseased animals and animal products, is most frequent in Africa, the Middle East and in Central and South Asia”.
MODE OF TRANSMISSION: It is the spore rather than the vegetative form that is the agent by which the disease is transmitted and it is doubtful that the vegetative form ever proliferates significantly outside the animal body.
Although definitive studies are lacking, infection of animals mainly results from contaminated dust and transmission by biting flies as less frequent possibilities.
The most common mode of transmission to humans is by the entry of spores from infected animal products through lesions of the skin, specially in exposed parts of the body such as the arms, face and neck. More rarely, infection is by ingestion of meat of infected animals or by inhalation of spores, as form contaminated wool, hair or hides. THERE ARE NO DOCUMENTED CASES OF PERSON-TO-PERSON TRANSMISSION.
Animal experiments, including experiments in non-human primates, suggest that the introduction of only a few spores through lesion is likely to initiate cutaneous or gastrointestinal infection but that a much larger number of spores is required to produce a high probability of respiratory infection.
INCUBATION PERIOD: Symptoms of human cutaneous and gastrointestinal anthrax generally appear within one to several days after exposure. Reported incubation periods for inhalation anthrax range from one to six weeks, with most cases appearing within the first two weeks or perhaps sooner in persons receiving high doses.
Prolonged incubation periods for inhalation anthrax are attributed to spores that remain dormant in the lungs for considerable periods before germinating and initiating systemic infection.
CLINICAL FEATURES: Cutaneous infection starts as painless, non-scarring, pruritic papule progressing over a period of about a week to a black depressed eschar with swelling of adjacent lymph glands and localised oedema, which may become extensive. Although usually self-limiting, untreated cutaneous anthrax can become systemic and is fatal in five to 20 per cent of cases. With proper antibiotic therapy, the death rate of cutaneous anthrax is less than one per cent.
Inhalation anthrax begins with nondescript or flu-like symptoms that may elude correct diagnosis. These may include fever, fatigue, myalgia, headache, chills, non-productive cough and vomiting, followed after one to three days by the sudden development of dyspnea, cyanosis, shock, coma and death.
Chest X-rays often show a widened mediastinum and marked pleural effusion and during terminal stages blood levels of vegetative bacilli may reach 108 or more per ml. although late administration of antibiotics may sterilize the blood while not preventing death from the action of anthrax toxin already released.
The average time between onset and death is one to seven days, with reported case fatality rates of 80 per cent and higher. Meningitis is not uncommon. Pneumonia may be present but is not a regular feature. Despite its name, therefore, inhalation anthrax is not a true respiratory disease, in that the lungs usually remain clear of growing bacteria until late stages.
Gastrointestinal and oropharyngeal anthrax result from the ingestion of contaminated meat. Gastrointestinal anthrax may be accompanied by fever, nausea, vomiting, abdominal pain and bloody stools. Oropharyngeal infection is characterised by oedematous swelling of the neck, often massive and accompanied by fever. Mortality in gastrointestinal anthrax is variable, depending on the outbreak, but in some outbreaks is reported to approach that of inhalation anthrax.
