Pox (boshonto) an eruptive disease of the skin and mucous membrane of the body caused by virus. Of the two major types of pox, smallpox which is caused by the virus variola major is a very serious illness, while the chickenpox caused by varicella virus is relatively mild. The former has been eradicated from Bangladesh while the later is relatively a common disease of childhood.

Smallpox (gutiboshonto) An acute, contagious, systemic viral disease characterized by an eruption that passes through the successive stages of macules, papules, vesicles, pustules and crusts. Smallpox (variola major) is a classical disease afflicting mankind, but is also the one which greatly contributed to the development of vaccination against microbial infections. It is a systemic infection, that is, the virus infects and multiplies in the blood.

The major manifestation of the illness is the appearance of severe skin lesions all over the body and in the eye, often causing blindness. Epidemics of smallpox used to be quite a regular seasonal phenomenon in the region now comprising Bangladesh causing considerable morbidity and mortality. The virus causing chicken pox is not, related to smallpox virus and is not a member of the Poxviridae family.

Table Smallpox victims and deaths, 1950-1977.

Year Cases Deaths Year Cases Deaths
1950 21273 9445 1964 69 42
1951 38871 30341 1965 316 142
1952 10490 8053 1966 3207 1491
1953 1102 788 1967 6648 3455
1954 445 188 1968 9039 4024
1955 1926 979 1969 1925 597
1956 4962 3170 1970 1473 502
1957 24920 18149 1971 N/A N/A
1958 79060 58891 1972 10754 3262
1959 15048 9508 1973 32711 9354
1960 1905 1271 1974 16485 2780
1961 660 469 1975 13798 2492
1962 610 379 1976 0 0
1963 3735 2847 1977 0 0

The Persian physician Al-Rhaze about AD 900 wrote the first known account of smallpox separating the disease from measles. Bishop Marius earlier in 570 mentioned the disease under the term 'variola'. In about 1200 Gilbert of England first referred to smallpox as a contagious disease. Thomas Sydenham in 1675 described the disease in more detail. William Heberden in 1767 first clearly distinguished chickenpox from smallpox.

Smallpox was pandemic in Europe during the first quarter of the 17th century, epidemic in England during 1666-1675, and there were scattered outbreaks in New England all through the 17th century. Until during the middle of the 20th century smallpox was one of the killer diseases in all the continents of the world.

The disease had prevailed for centuries in Bangladesh. Treatment of smallpox was commonly practiced by indigenous practitioners, the 'kabiraj'. Some specific remedies were used for the treatment of smallpox and these were mentioned by the Magistrate of noakhali in his Annual Report for 1874-1875: 'In 'bara pira', or smallpox, three remedies are used viz, 1. juice of the akan tree and mustard rubbed into the neck and throat; onions, plantains and soaked rice are given as diet, with hot water fomentation and bathing; 2. a mixture of alligator (crocodile) flesh, honey and night soil; 3. juice of biskatali and bara poddo are mixed together and poured down the throat, nose and ears'.

The most significant event in the history of smallpox in Bangladesh from the 19th century until 1961 was the massive epidemic of 1957-1959. It was reported that over 1,15,000 cases and 86,000 deaths occurred in those three years.

The Smallpox Eradication Scheme in Bangladesh (then East Pakistan) was launched in 1961, with the goal of mass vaccination of the entire population within a two-year period, from July 1961 to June 1963. To deal with the problem of controlling the susceptible, a well-organised mass vaccination campaign followed by regular systematic vaccination programme was the remedy.

Seventy-five million vaccinations were recorded during 1961-1963. An additional 68 million vaccinations were reported during 1964-1966, which included the maintenance phase of the scheme. In 1970, from January-August, 1,473 cases and 502 deaths were reported, of which 96 percent had occurred in only four districts: Mymensingh, Sylhet, Bogra and Tangail.

During 1971, the year of the struggle for liberation, vaccination and surveillance activities continued, but were somewhat disrupted. All outbreaks during the first four months of 1972 were traceable to importation from India. During the war of 1971 several million Bangladeshis left the country for India. Most of them were housed in crowded camps; the largest, near Calcutta, was the Salt Lake Camp which sheltered an estimated 200,000 to 300,000 refugees. Government priority was given to supplying food, shelter, sanitary facilities and treatment for acute diarrhoeal diseases. Under such circumstances epidemics of infectious diseases were predictable. In late 1971 smallpox broke out in Salt Lake Camp, but it was not immediately recognized. Importation of smallpox followed the liberation of Bangladesh in December 1971, when refugees returned from India to their new country. Active smallpox cases, others in the incubation period, and unvaccinated contacts were all loaded together on trucks for the trip to the border.

During February and March 1972, eight districts were infected by importation: Rangpur, Rajshahi, Kushtia, Jessore, Khulna, Faridpur, Barisal and Patuakhali. From a survey of one-sixth of the villages in Nesarabad (Swarupkati) upazila, Pirojpur, it was estimated that over 2000 smallpox cases had occurred in the upazila during February and March. All investigated outbreaks were traceable to importation with sources of infection in the refugee camps, in crowded transport en route to Bangladesh, or in transit camps. By this time the official WHO global strategy for smallpox eradication had been established as surveillance, the detection of smallpox outbreaks and containment, case isolation and contact vaccination. This strategy was adopted in Bangladesh. In the post-liberation period major efforts were made to re-establish the eradication programme, especially in the infected areas.

In February 1975 a presidential directive was issued which declared smallpox a national emergency and ordered the mobilization of all available resources to assist the Smallpox Eradication Programme. International aid was also requested. In an attempt to interrupt this rapid spread new objectives were defined: detection of 80 percent of new outbreaks within 15 days of the date of onset of the first case; containment, so that no new case occurred 15 or more days after the date of detection; and identification of the source of 90 percent of outbreaks.

To meet these objectives, programme operations were strengthened. Despite the rapid increase in resources and the full commitment of the Government, the number of outbreaks continued to rise during April. Each new outbreak was examined critically and problems of detection and containment were identified. New solutions evolved and new procedures were developed based on field experience. As a result of the seasonal drop in smallpox transmission and improved methods of detection and containment, the number of outbreaks began to fall rapidly in May, 1975. By the end of the monsoon season smallpox transmission had been interrupted in most districts. The last case of smallpox had occurred on 16 October 1975 following which, in 1977, Bangladesh was officially declared as smallpox free country at a time when cases of smallpox were still being detected in East African countries. But eradication campaign in East African countries was rapidly heading towards a successful completion, and within another 2 years, in 1979, the continent was declared smallpox free and global eradication of smallpox was thus achieved.

Chickenpox (jolboshonto) An acute, infectious disease caused by the virus Varicella, a member of the Herpesvirus group. Chickenpox is a disease of childhood and is not considered serious, and generally lasts about two weeks after the first appearance of symptoms. The route of entry of the virus is probably the mucosa of the upper respiratory tract. In Bangladesh the disease occurs sporadically without marked seasonality, but appears to be more common during the dry months of spring and early summer coincident with the heavy dust load of the air at that time.

Early symptoms of the disease include malaise and fever followed by appearance of rash first on the trunk and then on the face, limb and the mucosa of mouth and pharynx. Successive crops of vesicles appear within a few days that carry watery fluid inside. The disease is thus came to be called in Bangla 'jolboshonto' (jol meaning water, and boshonto means pox). The skin lesions do not leave permanent scars on healing, as opposed to smallpox lesions, nor does these usually affect vital organs such as the eye. Outbreaks of chickenpox in Bangladesh are relatively mild and the disease is not regarded as a significant public health problem. As such no prophylactic measures are usually recommended in uncomplicated cases of chickenpox. [SM Humayun Kabir and Zia Uddin Ahmed]

See also vaccination; viral diseases.