Spring and summer bugs
We’re rapidly approaching the beginning of the Lyme disease season. But, it’s not the only disease spread by insects.
Globalization has fueled a trend of emerging and reemerging infectious diseases, and it can be easy to forget that six- and eight-legged creepy crawlies still spread disease.
It took only two decades from when it was first reported in 1975 for Lyme disease to become the most common insect-transmitted disease in the country. Officials from the Centers for Disease Control say that while only 30,000 cases are diagnosed each year, there may be as many as 300,000 actual cases of the disease.
Lyme disease is spread by the deer tick, an arachnid common to the American Northeast, Midwest and the Great Lakes states, and is caused by a bacterium called Borrelia burgdorferi. These ticks are about the size of a sesame seed, but baby ticks, called nymphs, are almost invisible. Since their bite is usually painless, many people never notice they’ve been bitten.
One symptom can be a tell-tale red “bulls-eye” rash appearing from three days to a month after the bite. Other symptoms include joint pain, chills and fever and fatigue. If Lyme disease goes undiagnosed, more serious symptoms can appear weeks to years after the tick bite and include severe headaches, arthritis, joint swelling and, in rare cases, heart and central nervous system damage. Fatalities are uncommon. Lyme can be treated with antibiotics. The risk of getting Lyme disease is greatly reduced if the tick is removed within 36 hours.
Rocky Mountain spotted fever
Cases of RMSF have been diagnosed since 1920 but since 2001 the number of cases has been rising. The cause is the bacterium Rickettsia rickettsia, and it’s spread primarily by the American dog tick, with 60 percent of cases found in North Carolina, Oklahoma, Arkansas, Tennessee and Missouri. Most cases are reported from April though October.
Early symptoms include fever, headache, abdominal and muscle pain, vomiting and sometimes a red rash. If it’s not treated quickly, RMSF can cause serious damage to kidneys, lungs, heart and the brain, and can be fatal. The disease is treated with antibiotics.
Ticks live in tall grass and low bushes at the edges of forests, but they can be found in lawns and gardens as well. If you are walking through areas that might be tick infested, avoid wearing shorts and sandals and use insect repellent that contains DEET or permethrin. Check for ticks and remove them using tweezers, grasping the tick where the head enters the skin. Pull firmly outward and clean the bite with rubbing alcohol. Don’t forget to check clothing, kids and pets.
West Nile virus
West Nile was first reported in Queens, New York, in 1999. Within ten years it had spread across the country. Disease-carrying mosquitoes are found in the lower 48 states and the District of Columbia.
West Nile is spread by the bite of an infected mosquito. In 80 percent of people, there are no symptoms. In the other 20 percent, the first symptoms include body aches, fever and vomiting. Serious cases can lead to inflammation of the brain, causing disorientation, convulsions and paralysis. West Nile is easy to diagnose with a blood test and is treated by managing the symptoms.
To avoid West Nile disease, use insect repellents containing DEET, wear long sleeves and pants from dusk to dawn, eliminate standing water around your home and support your local mosquito control programs.
Once considered an exotic illness, Chagas is starting to take hold across the country. This disease is caused by a protozoan parasite and is transmitted by kissing bugs, or triatomine bugs. The bugs bite a sleeping person who then scratches the bug’s feces into their bite wound.
Early symptoms include fever, body aches, eyelid swelling, nausea and swollen glands. Many people initially have no symptoms, but left untreated, Chagas can cause serious cardiac and digestive system complications, including sudden heart failure decades later. It is treated with anti-parasitics and by managing the symptoms. HLM
Sources: Dr. Bobbi Pritt, Director, Clinical Parasitology Laboratory, Mayo Clinic, Minnesota, mayoclinic.org, usatoday.com, washingtonpost.com and cdc.gov.
Zika virus threatens global spread
In May 2015, the first case of Zika virus was reported in Brazil; more than one million cases have been reported to date in Brazil, and the number of cases reported in the United States continues to climb.
Zika is transmitted through the bite of the Aedes aegypti mosquito and possibly by the Aedes albopictus. Symptoms of infection are a mild fever and a skin rash, along with conjunctivitis and muscle or joint pain.
According to the World Health Organization, the virus has been associated with a steep increase in the number of babies born with microcephaly, a rare condition that is associated with smaller-than-normal head size and incomplete brain development, to mothers who were infected while pregnant.
The CDC has advised pregnant women and women planning to become pregnant to delay their travel to nearly two dozen countries where Zika virus is present, and if they do travel, to talk with their health care provider and take precautions to avoid mosquito bites. These include frequent application of insect repellent, wearing clothes that cover as much of the body as possible, and avoiding exposure during times when Aedes mosquitoes are active.
Sources: cdc.gov and who.org.