Dr. Charles "Pat" Davis, MD, PhD, is a board certified Emergency Medicine doctor who currently practices as a consultant and staff member for hospitals. He has a PhD in Microbiology (UT at Austin), and the MD (Univ. Texas Medical Branch, Galveston). He is a Clinical Professor (retired) in the Division of Emergency Medicine, UT Health Science Center at San Antonio, and has been the Chief of Emergency Medicine at UT Medical Branch and at UTHSCSA with over 250 publications.
Mary D. Nettleman, MD, MS, MACP is the Chair of the Department of Medicine at Michigan State University. She is a graduate of Vanderbilt Medical School, and completed her residency in Internal Medicine and a fellowship in Infectious Diseases at Indiana University.
Monkeypox has a relatively recent history. It was first discovered in monkeys
in 1958, although a "vesicular disease in monkeys" was described in the1860s.
The disease, and eventually the causative virus, was named monkeypox because the
lesions (pox) seen in monkeys developed like other known pox-forming diseases
(pustules that eventually break open, ulcerate, crust over, and some pox form
scars in the skin). Later studies showed the "monkeypox" virus was actually
sustained endemically in African rodents. It was not until 1970 in Africa
(Zaire, now the Democratic Republic of Congo), when a 9-year-old boy (who
developed smallpox-like lesions) was the first person to eventually be diagnosed
with monkeypox. This situation initially caused concern that smallpox may also
have an animal reservoir or endemic population that would make eradication
of smallpox impossible. Fortunately, this was not the case because monkeypox was
found to be a different species of pox virus, and smallpox was eradicated from
the human population by vaccinations in 1979 (currently, only a few research
labs have access to smallpox viruses). Monkeypox is now the major Orthopoxvirus
that infects humans and fortunately, not frequently. However, vigilance is
warranted as there have been several outbreaks of monkeypox since the 1970s.
Although most have occurred in Africa (mainly western and central Africa), there
was an outbreak in the U.S. in 2003. This apparently happened when an animal
distributor either housed or transported monkeypox-infected African rodents
(Gambian rats) with prairie dogs that were later purchased as pets, became
"sick," and transmitted the disease to their owners.
What causes monkeypox? How is monkeypox transmitted?
Monkeypox is caused by an Orthopoxvirus named monkeypox. The viruses are oval
brick-shaped viruses that have a lipoprotein layer with tubules or filaments
that cover the viral DNA. There are many members of this viral genus, including
such species as variola (smallpox), cowpox, buffalopox,
camelpox, rabbitpox, and
others. Most species infect a particular animal species but occasionally may
infect other mammals.
Figure 1: Monkeypox virus, brick-shaped negative stained virus grown in
tissue cultures, visualized by electron microscopy; SOURCE: CDC/Cynthia S. Goldsmith, Inger K. Damon, and Sherif R. Zaki
Transmission of monkeypox is usually by direct contact with infected animals
or possibly by eating poorly cooked meat from an infected rodent or monkey.
Cutaneous or mucosal lesions on the infected animal -- especially when the human
skin gets bites, scratches, or other trauma -- are a likely source for virus
infection. Person-to-person transfer, probably by infected respiratory droplets,
is possible but is not often documented. One study suggested that only about 8%-15% of infections were transmitted person to person among close family
members.
The word "rash" means an outbreak of red bumps on the body. The way people use this term, "a rash" can refer to many different skin conditions. The most common of these are scaly patches of skin and red, itchy bumps or patches all over the place.
Lymph nodes help the body's immune system fight infections. Causes of swollen lymph nodes (glands) may include infection (viral, bacterial, fungal, parasites). Symptoms of swollen lymph nodes vary greatly. They can sometimes be tender, painful or disfiguring. The treatment of swollen lymph nodes depends upon the cause.
Chronic cough is a cough that does not go away and is generally a symptom of another disorder such as asthma, allergic rhinitis, sinus infection, cigarette smoking, GERD, postnasal drip, bronchitis, pneumonia, medications, and less frequently tumors or other lung disease. Treatment of chronic cough is dependant upon the cause.
Nausea is an uneasiness of the stomach that often precedes vomiting. Nausea and vomiting are not diseases, but they are symptoms of many conditions. The causes of vomiting differ according to age, and treatment depends upon the cause of nausea and vomiting.
Although a fever technically is any body temperature above the normal of 98.6 degrees F. (37 degrees C.), in practice a person is usually not considered to have a significant fever until the temperature is above 100.4 degrees F (38 degrees C.). Fever is part of the body's own disease-fighting arsenal: rising body temperatures apparently are capable of killing off many disease- producing organisms.
Travelers should prepare for their trip by visiting their physician to get the proper vaccinations and obtain the necessary medication if they have a medical condition or chronic disease. Diseases that travelers may pick up from contaminated water or food, insect or animal bites, or from other people include malaria, meningococcal meningitis, yellow fever, hepatitis A, typhoid fever, polio, and cholera.
Smallpox is a disease caused by the variola virus. Symptoms and signs include a characteristic rash and high fever. Treatment focuses on supporting the patient. Smallpox may be prevented with the ACAM2000 smallpox vaccine.
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