Thursday, April 13, 2017

Scientists Predict 2017 will be a Banner Year for Lyme Disease

Richared Ostfeld, an ecologist at the Cary Institute of Ecosystem Studies in Millbrook, N.Y. and Felicia Keesing, an ecologist at Bard College are husband and wife and experts in Lyme disease. They have predicted that 2017 will be a very risky year for getting Lyme disease in the northeast. Lyme disease is caused by Borrelia burgdorferi, a bacterium transmitted through the bite of infected blacklegged tick or deer tick. In general, ticks need to be attached for 36 to 48 hours before they can transmit Lyme disease bacteria. In general, ticks need to be attached for 36 to 48 hours before they can transmit Lyme disease bacteria. These ticks are usually found in wooded areas and have a two year life cycles. 

Since 1990, between 9,000 and 30,000 cases of Lyme disease have been reported annually to federal health officials. Although the true number of cases is unknown, nearly 30 000 confirmed cases were reported to the Centers for Disease Control and Prevention (CDC) in 2008 and 2009, that was the peak number of cases reported but not nearly the total number of likely cases. In a scientific study surveying large medical laboratories in the United States it was found that 3.4 million tests were conducted for Lyme disease in 2008; and it was estimate that 288,000 Lyme disease infections occurred among that patient population.

 Accurate diagnosis and effective treatment of Lyme disease is not always easy, particularly in regions of the country newly invaded by the epidemic. The symptoms of Lyme disease can be confusing and vague. Typical symptoms include fever, headache, fatigue, and a characteristic skin rash called erythema migrans (a bullseye rash). Lyme disease is diagnosed based on symptoms, and the possibility of exposure to infected ticks; laboratory testing is helpful if used correctly and performed with validated methods. However, the accuracy of lab tests has been generally poor in the past, though they are improving, the occurrence of Lyme disease may be vastly underreported and treated. If Lyme disease is left untreated for some time, B. burgdorferi may persist in the patient's tissues and can migrate to the central and peripheral nervous system or to joints and cause more-severe late-stage symptoms, which include arthritis and neurological disorders, such as dizziness, memory loss and disorientation.

Though Lyme disease is not a new disease it is spreading. Scientists Drs. Richard Ostfield and Felicia Keesing have been studying Lyme disease for more than 20 years. They have found that understanding the life cycle of the ticks that transmit Lyme disease bacteria can help in understanding the risk of getting the disease and strategies to avoid it. There is no vaccine to protect you so you have to prevent exposure. Drs. Ostfield and Keesing have come up with an early warning system for the disease. They can predict how many cases there will be a year in advance by looking at one key measurement: the size of the mouse population the year before. The explanation for why this works is simple: Mice are highly efficient transmitters of Lyme. According to the scientists mice infect up to 95 % of ticks that feed on them and are responsible for infecting the majority of ticks carrying Lyme in the Northeast. A single mouse can have up to 100 ticks covering its ears and face.

The complete life cycle of Ixodes ticks takes 2 years. Tick eggs are laid in the spring, and hatch as larvae in the summer. Larvae feed on mice, birds, and other small animals in the summer and early fall. The larvae may become infected with Lyme disease bacteria when feeding on these animals. Once a tick becomes infected, it stays infected for the rest of its life and can transmit the bacteria to other hosts. After this initial feeding, the larvae usually become inactive until the following spring, when they change into nymphs.

Nymphs seek blood meals in order to fuel their growth into adults. Nymphs feed on small rodents and other small mammals in late spring and early summer. Nymphs will also feed on humans, and if previously infected with Lyme disease bacteria, they can transmit the disease to humans. Nymphs molt into adult ticks in the fall. In the fall and early spring, adult ticks feed and mate on large animals, such as deer. Adult female ticks will sometimes also feed on humans. In spring, adult female ticks lay their eggs on the ground, completing the 2-year life cycle. The CDC reports that most people are infected through the bites of the nymphs which feed during the spring and summer months. The tiny nymphs are almost impossible to find on your body. Adult ticks can also transmit Lyme disease bacteria, but they are much larger and more likely to be discovered and removed before they have had time to transmit the bacteria.

The risk of exposure to ticks is greatest in the woods and in the edge area between lawns and woods; however, ticks can also be carried by animals onto lawns and gardens and into houses by pets. Now is the time to seal up all likely mouse entry points to keep mice out of the house. A mouse can fit through the narrowest gap, seemingly flattening themselves to crawl into the house. According to the Center for Disease Control a gap of a quarter of an inch or a hole the size of a pencil eraser is large enough for a mouse to enter. A systematic approach is best for sealing all entry points. First of all, there is no way to prevent mice from getting into the garage because garage doors just do not seal that tight in their tracks. Instead, it is necessary to keep all nesting material and clutter out of the garage and seal all entries to the house. Protect yourself from potential exposure to the nymph ticks in your home and garden.

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