Since prehistoric times, wars have killed combatants and civilians — by weapons but also by infections. In addition to creating crowded, unsanitary conditions, wars expose people to bacteria and viruses to which they have no immunity.

On April 10 in Century City, at the 15th annual meeting of the Society for Healthcare Epidemiology of America, Maj. Kimberly Moran, M.D., spoke about infections in military personnel returning from Afghanistan and Iraq.

Moran works at the Walter Reed Army Medical Center in Washington, D.C.

One of these diseases is leishmaniasis, nicknamed "Baghdad boil."

According to the Deployment Health Medical Research Library, maintained by the Department of Defense, leishmaniasis, which is found in 88 countries worldwide, is in fact three types of disease caused by protozoan parasites of the genus Leishmania:

• cutaneous leishmaniasis, which affects the skin;

• mucocutaneous leishmaniasis, which affects the skin and mucous membranes; and

• visceral leishmaniasis, which affects organs in the abdomen.

The bite of a number of species of sandflies transmits the protozoa to humans.

Cutaneous leishmaniasis, the more common form of the disease, is not fatal. But the visceral form can kill if it affects the liver, spleen or bone marrow, especially in immunocompromised patients (e.g., those with late-stage HIV).

According to John Halpern, director of the department of emergency medicine at the Coral Springs Medical Center in Florida, skin lesions can heal spontaneously within two to 10 months, but the mortality rate for untreated cases of visceral leishmaniasis ranges from 75 percent to 95 percent.

In cases of mucocutaneous leishmaniasis, death typically results from secondary infection.

Moran said that lesions are diagnosed as leishmaniasis if they last more than three weeks and do not respond to antibiotics, and if the patient is known to have been exposed to sandflies.

Since the invasion of Iraq, the U.S. forces have seen 827 cases of cutaneous leishmaniasis and five cases of visceral leishmaniasis.

"It peaked in the summer and fall of 2003," Moran said, "but has decreased since then because of education regarding protective measures, such as netting."

Although cutaneous leishmaniasis is self-curing, the Army Medical Corps treats cases when there are more than five lesions; when lesions are in such cosmetically important areas as the face, ears and backs of the hands; and when there is a risk that scarring would impair action of the joints or toes.

At Walter Reed, Moran said, patients are treated with Pentostam, a medicine licensed for use in the United Kingdom but not yet approved by our own Food and Drug Association.

Moran stressed that leishmaniasis is not transmitted by simple contact: "It requires a sandfly reservoir.

"But because of the potential for transmission through blood, anyone who served in Iraq, Kuwait or Afghanistan is deferred from donating blood for one year after their return to the States.

"Anyone who has suffered either cutaneous or visceral leishmaniasis is deferred for life."

Another sickness vexing the Army Medical Corps is acute eosinophilic pneumonia (AEP), defined in a study published by Dr. Andrew F. Shorr in the Dec. 22/29, 2004, issue of the Journal of the American Medical Association as a rare disease of unknown etiology (cause) "characterized by respiratory failure and eosinophilic infiltration of the lung."

Eosinophils, which constitute between 1 percent and 3 percent of the total white blood-cell count, play a major role in allergic reactions and can cause constriction of the air passages.

Although AEP is rare, Moran said the Army saw a marked increase in cases after the invasion of Iraq on March 19, 2003, with the majority of cases occurring in the summer of 2003.

From March 2003 through March 2004, Shorr and his fellow researchers identified 18 cases of AEP among the 183,000 military personnel then deployed in or near Iraq.

Of those cases, 16 were male, two were female. Their median age was 22.

The majority recovered after treatment with corticosteroids, but two of the patients died.

According to Moran, the cause of the disease remains a mystery.

None of the 18 had been exposed to any agent known to cause AEP, and Shorr's study discovered "no evidence of a common source exposure, temporal or geographic clustering, or person-to-person transmission."

However, Shorr found that all but one person reported "significant exposure to fine airborne sand or dust." In addition, all 18 patients used tobacco, and 14 had just recently taken up the habit.

Moran said that more than 60 percent of active-duty personnel smoke tobacco.

Then why have so relatively few contracted AEP (only 18 out of an estimated 109,800 smokers)?

In a telephone interview, Moran said, "There may be cofactors: smoking plus something. For example, dust."

In fact, there must be at least a third factor, since many thousands of all those smokers must also have been exposed to airborne sand or dust.

Another mystery is why, although Iraqis certainly do smoke, no similar cases of AEP among the Iraqi population have been reported to the Ministry of Health.

"But there may not have been the same surveillance of the Iraqi population as of the U.S. military," Moran said.

Or perhaps AEP was misdiagnosed.

The Armed Forces Institute of Pathology warns, "AEP may be mistaken for other diseases, particularly community-acquired pneumonia, resulting in delayed or missed diagnosis."

The third infection discussed by Moran, Acinetobacter baumannii, sounds like the scariest.

An opportunistic pathogen, A. baumannii is very difficult to treat, as it is resistant to many antibiotics.

"Two days after the war began in Iraq, we started seeing cases at the Landstuhl Regional Medical Center in Germany," Moran said.

"From seeing maybe one or two cases a year, we were seeing more than 20 a year.

"When we first noticed an increase, there was concern that A. baumannii, which is found in soil and water, was being traumatically implanted into soldiers when they were injured."

Remarking that A. baumannii has been in hospitals "for ages," Moran said it develops a reservoir in hospitals, then spreads from patient to patient among the immunocompromised.

So far, A. baumannii has caused no fatalities in soldiers at Walter Reed, but there have been four deaths among immunocompromised civilians (not all patients at Walter Reed are active-duty soldiers).

A. baumannii is spread by contact, not by the respiratory route.

Moran mentioned the conflict between sequestering patients, in order to contain a bacterium, and their rehabilitative need for interaction.

At Walter Reed, therefore, hand washing is strictly enforced, patients with A. baumannii are kept in one wing of the orthopedic ward, and they must "gown-and-glove" when visiting friends in their unit.

"Cohorting — keeping affected patients together — is a mainstay of the effort to control the spread," Moran said.

"We also try to prevent health-care providers from working with other patients after having worked with patients with A. baumannii.

"But that is hard to do logistically. Not only is there a nursing shortage, but nurses must go on breaks."