Rewriting the Book on Infectious Disease

“Still more interesting are those situations where we have cryptic infection, infection not readily appreciated,” Dr. Lipkin said. “There are instances where viruses can infect cells. You see no evidence of damage whatsoever, but the cell doesn’t make a hormone that’s necessary. This is likely to be extremely important in some forms of diabetes and hypothyroidism.”

Current research is providing some very interesting information on the relationship between prenatal infection and certain behavioral disorders, and may hold the key to further understanding diseases such as cerebral palsy, epilepsy, and multiple sclerosis.

Prenatal Infection

Current research, he said, is providing some very interesting information on the relationship between prenatal infection and certain behavioral disorders, and may hold the key to further understanding diseases such as cerebral palsy, epilepsy, and multiple sclerosis. Going back decades, there have been data suggesting that exposure, in utero, to a variety of infectious agents triggers stimulation of the immune response, which results in damage to the developing fetus. Now researchers are discovering that the timing of prenatal exposure may determine how the infection manifests.

“As this has been modeled using a variety of different animal’s systems, it’s become clear that pathogenesis is not specific to the agent, but rather to the host immunoresponse,” Dr. Lipkin said. “And as you begin to understand more about the genetics of immunity, you can understand how these things might funnel through a common pathway to result in various sorts of common pathways for damage.”

One way in which this can be modeled, without considering a specific virus or bacterium, is to directly stimulate the immune response, which Dr. Lipkin said has been done using a double-stranded RNA molecule as a viral mimic that looks like a replicating virus and introducing this into animal models at different stages of gestation.

“Depending on when you’re exposed during the development of the central nervous system, you may have one manifestation or another,” he said. One model, for example, may lead to the expression of withdrawal behavior that looks like autism, while another exposed to the same agent at a different stage might look like attention deficit hyperactivity disorder.

“Now I’m not saying that all individuals with these kinds of disorders, in fact, have this as a result of prenatal infection,” Dr. Lipkin noted. “But this certainly speaks to biological plausibility and, if you put it together with what is known epidemiologically, it makes sense.”

Acute Infectious Disease

A topic of great concern to physicians and the general public is the potential for widespread human infection from animal viruses. Dr. Lipkin and his colleagues are part of a worldwide network of cutting-edge researchers on the front line of medical research in this area.