Diagnosis
of Smallpox
Strain
Variations of Smallpox
There are two
main strains of smallpox, variola major and variola minor. Variola
major, the more severe of the two, has two different forms and
numerous presentations which effect the severity and mortality
rate.
Variola major
Variola major
is the more common form, and was the only form known until the
end of nineteenth century. (19:3) It has
a more severe, more extensive rash, a higher fever, and a greater
degree of prostration. (19:3) The fatality
rate of variola major is 30% or higher. (19:3)
There are four
clinical types of Variola major: ordinary, modified, flat and hemorrhagic. (19:5) The
four clinical presentations of variola major, are based on the
nature and evolution of the lesions. The relative vigor of the
immune response probably determines the clinical presentation. (22:V3:23)
Ordinary
Smallpox
Ordinary smallpox
comes in two basic forms: the discrete type and the confluent type. (15:42) In
the case of discrete ordinary smallpox, the pustules stand out
on the skin as separate blisters, and the patient has a better
chance of survival. In confluent-type ordinary smallpox the blisters
merge into sheets, and it is typically fatal. [There is little
normal skin appearing between the pustules.] Ordinary smallpox
can also be Semi-confluent, where the pustules are extremely close
together on the face, but are discrete elsewhere on the body. (22:V3:28) More
than 90% of cases in both vaccinated and unvaccinated persons are
of the ordinary type, which corresponds to the classical description
of smallpox. (22:V3:7)
 
Modified
Smallpox
Modified smallpox
is a relatively milder in comparison to the other types of variola
major, and primarily occurs in previously vaccinated people. (22:V3:25) Modified
refers to the character of the eruption and the rapidity of its
development. The prodromal illness still occurs but may be less
severe than in the ordinary type. There is usually no fever during
evolution of the rash. The skin lesions tend to evolve more quickly,
are more superficial, and may not show the uniform characteristic
of more typical smallpox. The lesions are often few in number,
but could be numerous, or even confluent. Regardless of the number
of lesions, they usually evolve rapidly. Modified smallpox is rarely,
if ever, fatal, with death rates historically being 1% or less.
Flat Smallpox

Flat smallpox
(or malignant smallpox) is characterized by an abrupt onset and
prostrating constitutional symptoms that are similar to hemorrhagic
smallpox (i.e. high fever and head, back and abdominal pain). (9:4) Like
hemorrhagic smallpox, flat smallpox has a high mortality rate and
often results in death. The confluent lesions develop slowly, never
progressing to the pustular stage but remaining soft, flattened,
and velvety to the touch. (9:4) The skin
has the appearance of a fine grained, reddish-colored crepe rubber,
sometimes with hemorrhages. (9:4) If the
patient survives, the lesions gradually disappear without forming
scabs or, in serious cases, large amounts of the epidermis might
peel away. (9:4) The rash on the tongue and
palate is usually extensive, and the skin lesions develop very
slowly. (22:V3:31) It’s not known with
certainty why some people develop this type of disease, but many
cases occurred in children. (22:V3:31) The
clinical course of flat smallpox is like that of burn or Stevens-Johnson
Syndrome patients. (22:V3:32-38)
Clinical symptoms
of flat type smallpox include: sudden onset, Temperature ranging
between 38.3¾C & 38.9¾C, Malaise, headache, general muscle
aches, backache (often severe), chest pain and anxiety… characterized
by a “peculiar mental alertness”. Patients can also
have abdominal pain, vomiting, and melena because of mucosal/submucosal
hemorrhage. In cases involving mucosal/submucosal hemorrhage an
acute abdomen may lead to laparotomy. Symptoms associated with
days 2 & 3 include: tachycardia, irregular petechial and macular
rash of chest, neck, back, upper arms, dusky erythema of face:
marked intracuticular edema, and a scalded appearance of skin,
like severe sunburn. Vesicles are 4-5 mm, superficial, flattened.
Symptoms associated with days 8-11include skin vesicles that are
soft, flat and velvety, some with huge confluent bullae (like Stevens
Johnson Syndrome). Symptoms associated with days 12-13 are: massive
exfoliation (like a severe burn), keratitis leading to blindness,
hemoptysis, uterine hemorrhage, an absence of platelets, neutropenia
and lymphocytosis. Symptoms connected with third week involve:
an inability to eat or drink, from severe throat pain with swallowing,
huge areas of skin peeling off with even slight pressure: Widespread
stripping of epithelium, “mortification” from tissue
destruction, fetid odor. Other third week symptoms include bacterial
sepsis and death (70%) from severe tissue destruction.
Hemorrhagic
Smallpox

The most extreme
type is flat hemorrhagic smallpox, in which the skin does not blister
but remains smooth. It darkens until it can look charred, and it
can slip off the body in sheets. (15:42) It
occurs in about 3 to 25% of fatal cases. (15:42) Hemorrhagic
smallpox is more common in teenagers, (15:42) and
pregnant women appear to be unusually susceptible. (9:4)
Illness usually
begins with a somewhat shorter incubation period and is characterized
by a severely prostrating prodromal illness with high fever and
head, back and abdominal pain. (9:4) “Intense
prostration” with severe headache and backache. The prodrome,
which can be prolonged, is characterized by fever, intense headache
and backache, restlessness, a dusky flush or sometimes pallor of
the face, extreme prostration and toxicity. (22:V1:14) Patients
tend to be alert, but apprehensive. There is little or no remission
of fever throughout the illness. Hemorrhagic manifestations can
occur early or late in the course of the illness. (22:V1:14) In
those cases in which it occurs early in the illness, the hemorrhagic
manifestations appear on the second or third day as subconjunctival
bleeding, bleeding from the mouth or gums, and other mucous membranes,
petechia in the skin, epistaxis, and hematuria. (22:V1:14) These
patients will have a quickly progressive disease course and often
develop signs and symptoms of inflammatory shock. (22:V3:47) Death
often occurs suddenly between the fifth and seventh days of illness,
when only a few insignificant maculopapular cutaneous lesions are
present. (22:V3:44)
Hemorrhagic
manifestations, when they do develop, the rash it may not look
at all like smallpox. (22:V1:46) It can appear
as blotchy, blanching erythema on arms and trunk. Petechiae and
hemorrhage in the mouth and on the skin can occur. The patients
may develop superficial vesicles. Acute Respiratory Distress Syndrome
is also possible. Blood counts may suggest leukemia, and include
myeloblasts.
Variola Sine
Eruptione
It is possible
to be infected with smallpox, but not erupt in the rash. Patients
experience the symptoms common to the prodrome, but it is usually
of short duration. In order to diagnose this infection, laboratory
workup is required. (22:V3:24) Symptoms of
this unusual type of smallpox include: a fever of 39¾C, headache,
backache, recovered in 48 hours.
Variola Minor (alastrim)
Variola minor,
also called a varioloid rash (15:41), was
first described in South Africa in 1904 and in the United States
in 1913. It was endemic in some countries in Europe and North and
South America, and in many parts of Africa. It is a less severe
disease, with a case fatality rate of 1% or less. (9:3) The
last naturally occurring case occurred in Somalia in October 1977.
Recognized strains of variola minor include alastrim, kaffir, and
amass.
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