NewsShare Member Profile: Leonard Marcus

Karl Neumann, MD

Like most ISTM members, Len Marcus has a long string of titles, accomplishments and travel-related interests associated with his name. But he is probably the only member whose titles include both an MD and a VMD, veterinary medical doctor. The textbooks in his consultation room are neatly divided into two categories: human and animal diseases _ with Len having written important chapters for books in both categories.

While growing up in Philadelphia, by the age of five, he already had a small museum of "snakes, salamanders, bugs and anything else that I could find crawling under the rocks in nearby Fairmount Park." There was never a doubt in his mind that he would become involved in a profession that had to do with nature and animals. He became a veterinarian first. Why did he later become a physician? "I wasn't smart enough to take care of more than one species at a time. So I went back to medical school to concentrate on treating humans," says Len, with his usual wit and dry sense of humor.

Len's accomplishments and interests form a three-dimensional web, and there is no single field that personifies him. He is board certified in veterinary pathology. He has specialty training in tropical medicine and parasitology. He can draw together facts and well thought-out opinions that in other settings usually take an entire committee of different health professionals.

While Len no longer practices veterinary medicine _ he doesn't even take care of his own cat ("That would be like taking care of family.") _ he remains active in the field, giving lectures and seminars in parasitology, insect and tick-borne diseases, and zoonoses to lay, medical and veterinary audiences. He now spends most of his professional time practicing travel medicine.

Len says that questions about exposure to animals should be a routine part of the evaluation of a sick patient in infectious disease and tropical medicine practices. Patients do not always volunteer information about contact with animals, and health care professionals may not ask relevant questions. Len's veterinary training leads him to ask for details about exposure to animals that help him deal with the epidemiology or management of some of his most interesting cases.

In a recent article, Emerging and Re-emerging Zoonoses in Veterinary Practice that appeared in DVM: the News Magazine of Veterinary Medicine, Len says there are changing patterns in the interrelationship of diseases in humans and animals. For example, acquired immune deficiency syndrome and iatrogenic immunosuppression have resulted in a rapidly expanding reservoir of people susceptible to opportunistic infections, many of which are zoonotic. Examples of zoonoses that may be particularly severe in immunosuppressed individuals include toxoplasmosis, giardiasis, cryptosporidiosis, babesiosis and bartonellosis.

Immunosuppressed individuals and their families should be educated about the type of pets to own (and not to own), how to handle the pets (disposing of excrement, for example), and notifying the veterinarian when a family member becomes immunosuppressed. Also, more than half of the antibiotics that are manufactured in the U.S. are used for livestock production, very likely contributing to antibiotic resistance in humans. And international travel brings an increasing number of people in contact with exotic diseases. Animals and animal products are transported internationally with increasing frequency and speed. Illegal trade in wildlife is second only to illegal trade in drugs.

Len is also interested in the effects of zoonotic diseases on another subgroup of the population, pregnant women and their fetuses. In a sense these too are immunosuppressed. They are more susceptible to some infectious diseases, tend to have more severe cases, and may be more at risk from the side effects of the medications than the general population. He often consults on the likelihood of fetal infection from various parasitic diseases, and options of therapy during pregnancy.

Some years ago, Len and his wife Eugenia, a pediatrician, wrote an editorial for the New England Journal of Medicine, commenting on an article describing an epidemic among mostly premature infants in an intensive care nursery (ICU) caused by the yeast, Malassezia pachydermatis. The yeast was first described as a cause of exfoliative dermatitis in a captive rhinoceros and has subsequently been found to cause ear infections in dogs. Likely, in this ICU outbreak the yeast was brought into the nursery by a health care worker who acquired it from his/her dog. Culture of the dogs belonging to the workers employed in this ICU found that 12 out of 39 dogs carried the yeast. Besides the usual hospital infection control methods, health care workers should treat their pets when they are ill, says Len.

Len attended college at Pennsylvania State University, received his veterinary degree from the University of Pennsylvania in 1962 and his MD from the Albert Einstein College of Medicine in New York in 1969. He completed an internship in pediatrics at Stanford University and a two-year post-doctoral fellowship in Tropical Public Health at Harvard. He supervised the Parasitology Laboratory of the Massachusetts Department of Public Health and taught veterinary and medical parasitology at Tufts University before going into full time private practice.

Like most ISTM members, Len likes to travel and has done quite a bit of it. He has spent time overseas in various parts of the world doing research, teaching and providing health care to local people.

Len is a white water rafting and canoeing enthusiast and a certified SCUBA diver. He likes fishing, hiking and wildlife photography. He shares his interest in wildlife with his son, a wildlife biologist, and his daughter, a high school science teacher. He is an active member and supporter of a number of organizations involved in ecology, wildlife conservation, and the natural sciences.