Smallpox mortality rate

DNA viruses Poxviruses Variola Vaccinia Large particles 200 x 250nm complex symmetry Variola is the smallpox virus. It produces a systemic infection with a characteristic vesicular rash affecting the face, arms and legs, and has a high mortality rate. Vaccinia has been derived from the cowpox virus and is used to immunize against smallpox... 

Smallpox Smallpox is a very contagious disease with a mortality rate as high as 30-35%. It is estimated that smallpox was responsible for 300-500 million deaths in the 20th century. Fortunately, it has been eradicated in 1979 through strict regimens of vaccination. 

Agent Index A336 Class Index C24 Smallpox Type Virus Initial symptoms are flulike including headache, chills, high fever (106° to 107°F), and aches in back and limbs. An Initial macular rash appears progressing to papules, and then blisters. The blisters in turn form crusts. The blisters and crusts cause severe itching. Routes Inhalation Abraded Skin Mucous Membranes Secondary Hazards Aerosol Contact Body Fluids Fomites Incubation 7 to 16 days Mortality Rate < 35% Reservoir Humans Direct Person-to-Person Transmission is possible. 

Vidarabine is used mainly in human HSV-1 and HSV-2 encephalitis, decreasing the mortality rate from 70 to 30%. Whitley et al. (57) reported that early vidarabine therapy is helpful in controlling complications of localized or disseminated herpes zoster in immunocompromised patients. Vidarabine also is useful in neonatal herpes labialis or genitalis, vaccinia virus, adenovirus, RNA viruses, papovavirus, CMV, and smallpox virus infections. Given the efficacy of vidarabine in certain viral infections, the U.S. FDA approved a 3% ointment for the treatment of herpes simplex keratoconjunctivitis and recurrent epithelial keratitis, and a 2% IV injection for the treatment of herpes simplex encephalitis and herpes zoster infections (Table 43.3). A topical ophthalmic preparation of vidarabine is useful in herpes simplex keratitis but shows little promise in herpes simplex labialis or genitalis. The monophosphate esters of vidarabine are more water-soluble and can be used in smaller volumes and even intramuscularly. These esters are under clinical investigation for the treatment of hepatitis B, systemic and cutaneous herpes simplex, and herpes zoster virus infections in immunocompromised patients. 

The vaccine is given by intradermal inoculation. A vesicle develops in 5 to 7 days and forms a scab that falls off in another 1 to 2 weeks. For healthcare workers who have been exposed to the virus, it is important to remember that if not immunized previously, you have about 3 to 4 days to obtain the smallpox vaccination. If given after that time, you will have the same 30% mortality rate as unvaccinated victims. Those patients who are known contacts should get VIG (0.6 mg/kg IM) within the first week of exposure. Those receiving this within 24 hours of exposure get the highest level of protection. 

The smallpox virus brought to the Americas by European setders had a devastating effect on the Native American population, who had not developed any immunity to the disease. The mortality rate among Europeans was around 30 percent compared with about 50 percent for the Cherokee and the Iroquois, 66 percent for the Omaha and the Blackfeet, 90 percent for the Mandan, and 100 percent for the Taino Indians. 

Smallpox can be transmitted by inhalation of the virus suspended in aerosols. After about a 12-day incubation period, infection from smallpox causes fever and headache. As the virus spreads to the skin it forms pus-filled vesicles across the body. Survivors usually are noticeably scarred for life. The mortality rate for immunized individuals is approximately 3 percent, while for non-immunized humans it increases to 30 percent. 

Three quarters of endemic cases of variola major fell into the classic, or ordinary, variety (see Figure 27-1). The fatality rate was 3% in vaccinated patients and 30% in unvaccinated. Other clinical forms of smallpox were associated with variola major, and it is likely that differences in both strain virulence and host response were responsible for these variations in clinical manifestations.68 Flat-type smallpox, noted in 2% to 5% of patients, was typified by (a) severe systemic toxicity and (b) the slow evolution of flat, soft, focal skin lesions (Figure 27-3). This syndrome caused 66% mortality in vaccinated patients and 95% mortality in unvaccinated. Hemorrhagic-type smallpox, seen in fewer than 3% of patients, was heralded by the appearance of extensive pete-chiae (Figure 27-4), mucosal hemorrhage, and intense toxemia death usually intervened before the development of typical pox lesions.69... 

Jenner, Edward (1749-1823) A surgeon and anatomist bom in England, Jenner experimented with cowpox inoculations in an attempt to prevent smallpox, a virulent infectious disease of ancient origin with a high rate of mortality that killed millions of people. In the early nineteenth century, Jenner successfully developed a method of vaccination that provided immunity from smallpox and late in life became personal physician to King George IV. The smallpox vaccination was made compulsory in England and elsewhere, and the disease was declared eradicated worldwide in 1979. 

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