BY JOHN RASWEILE
As a young scientist, I trained as a post-doctoral fellow with the Tulane University School of Public Health and Tropical Medicine. Long before Babesia became part of our local lexicon, I was searching for this and other causes of zoonotic diseases (i.e., those transmissible from animals to man) in the jungles and rural areas of Colombia. I therefore have a particular appreciation for the dangers posed by the current prevalence of ticks and tick-borne diseases on Long Island.
With the elimination of natural predators and changing land use practices, our deer population has increased to excessive and environmentally unsustainable levels. As the deer provide bountiful sources of blood for ticks at their adult reproductive stage, tick populations have also exploded. This, in turn, has contributed to a dramatic rise in the frequency of tick-borne zoonotic diseases in humans.
According to the Centers for Disease Control and Prevention, at least 14 tick-borne diseases now occur in the U.S, and eight of these have been reported on Long Island. For five of these, the number of cases recorded for Suffolk County by the state health department in 2013 (the latest reporting year) was as follows: anaplasmosis (34), babesiosis (193), ehrlichiosis (46), Lyme (566), and Rocky Mountain spotted fever (8). Some might view these numbers as being inconsequential, but that would be a serious mistake. The CDC has estimated that Lyme disease is actually under-reported in the United States by a factor of 10, and many people infected with Babesia never become symptomatic. Furthermore, some people become infected simultaneously with more than a single disease. These diseases can kill or make some individuals very sick, sometimes chronically for the remainder of their lives.
In recent years, the mortality rate for patients afflicted with anaplasmosis has hovered between roughly one percent and three percent, and for those with clinically-apparent babesiosis about five percent. Again, however, these numbers do not tell the full story. For those belonging to high-risk groups (e.g., the very young, elderly and immune-compromised individuals), threats of infection and death are significantly increased. The prevalence of asymptomatic cases of babesiosis is also problematic. Since there is no approved screening test for this disease in blood donors or donated blood products, seemingly healthy individuals can pass life-threatening infections to recipients via donated blood. According to a study published in 2011 in the Annals of Internal Medicine, at least 159 cases of babesiosis resulted from transfusions with infected blood or blood components between 1979 and 2009 (with the most occurring between 2000 and 2009). Many of these cases involved premature infants or elderly surgical patients already struggling with other health issues.
Statistics on tick-borne diseases also generally fail to convey the misery brought to individual patients. Recently, 30-year-old Canadian singer Avril Lavigne revealed that she had been bedridden for much of five months with a devastating case of Lyme disease. This included months of being undiagnosed despite consultations with several doctors, a frustrating and not uncommon problem for Lyme disease patients. Even medical doctors are not immune to such problems.
In 1993, Neil Spector, a well-trained physician now at the Duke Cancer Institute, began to experience health problems. For four years doctors failed to identify the cause as Lyme disease, even suggesting that the mysterious symptoms might be figments of his imagination. By 2009 the disease had sufficiently damaged Dr. Spector’s heart to require an emergency heart transplant, as now recounted in his book, “Gone in a Heartbeat.” While these dramatic examples are part of the public record, both communicable disease statistics and public venting indicate that human tick-borne infections have now reached intolerable levels on the East End.
To a substantial extent, such diseases in humans are also preventable. These were much less of a problem before the deer and tick populations exploded. Furthermore, careful studies conducted elsewhere have established that a reduction in deer populations lessened or eliminated the occurrence of at least the most common disease (Lyme) in humans. All safe and humane methods for reducing our deer population are still not being used. We cannot allow vocal minorities who are in denial about the deer-tick connection, or who wish to preserve excessive deer densities for sporting purposes, to dictate how society can respond to a public health crisis.
People’s lives and long-term quality of life are at stake.
Finally, as bad as the recent record is, there is reason to fear that we may not have seen the worst of tick-borne diseases in the U.S. Data reported on the CDC website indicate that cases of the most common diseases generally continue to trend upward. In Suffolk County, we have several species of ticks, far too many ticks, a superabundance of deer to promote tick reproduction and a variety of demonstrated or potential reservoir hosts to maintain the diseases in the environment.
At any time, new tick-borne diseases or tick species could be introduced. For example, according to the CDC and the World Health Organization, infections with tick-borne encephalitis viruses (TBEV) are common and often serious across large parts of Europe and Asia. These can cause long-lasting or permanent neurologic sequelae and have mortality rates varying from one percent to five percent for the European form and 20 to 40 percent for the Far Eastern strain.
TBEV are harbored and spread by Ixodes ticks. On Long Island, we have plenty of black-legged ticks (Ixodes scapularis), the local vector of Lyme disease, and cases of TBEV have already been detected in U.S. travelers to Europe and China. The dangerous, tick-borne Powassan virus (a flavivirus of the same genus as TBEV) has now been found in upstate New York and Connecticut. Dealing aggressively with our deer and tick problems is long overdue.
Dr. John Rasweiler is a retired medical school professor and a Cutchogue resident. He serves on Southold Town’s deer management committee and the Suffolk County control advisory committee and is also a North Fork Deer Management Alliance board member.