Vector borne diseases result in approximately one million deaths annually. Vector-borne diseases include flies, ticks, and mosquitos. These arthropods transmit viruses, bacteria, and spirochetes resulting in diseases such as West Nile Virus, Dengue, Colorado Tick Fever, Spotted Fever Rickettsiosis, Tularemia, Tick-Borne Relapsing Fever, Southern Tick-Associated Rash Illness, and Lyme Disease.
WEST NILE VIRUS
West Nile Virus results from a Culex mosquito bite. Most of the infections are asymptomatic. If symptoms result, they include headache, fever, fatigue, and muscle cramps. In rare cases, a rash on trunk and torso may appear. Severe cases include encephalitis and meningitis. It is diagnosed by the presence of IgM antibody in the cerebral spinal fluid. Treatment is supportive. Preventative therapy includes DEET.
This virus results in approximately 22,000 deaths. It is mostly found in Southeast Asia, Caribbean, and Americas. It manifests as either dengue without warning signs, with warning signs, or severe. The illness manifests as febrile, critical, and recovery. Febrile phase represents high temperatures with nausea, headache, muscle aches, and vomiting. The critical phase lasts 24-48 hours. Critical phase represents low blood pressure and volume leakage. Recovery phase is approximately 3-5 days. Diagnosis is based on serum samples. Treatment is supportive with fluid replacement. Preventative therapy includes vaccination approved in Brazil, Philippines, and Mexico.
SPOTTED FEVER RICKETTSIOSIS
Ixodid ticks host two bacterial types resulting in Rocky Mountain Spotted Fever. This disease is mostly found in men, Native Americans, and adults 40 years and older. Fever, rash, and headache are the main symptoms. The rash appears on the ankles, wrists, and forearms spreading to the trunk, palms, and soles. Diagnosis is based on serum samples. Treatment includes anti-biotics such as doxycycline and chloramphenicol.
A bacteria of two types A and B. It is extremely severe in humans. It is transmitted via flies and ticks and contaminated food, water, and animal tissue. It manifests as a sudden onset of fever, cough, sore throat, headache, fatigue, vomiting, and muscle aches. Tularemia’s hallmark characteristic is an elevated temperature without an increase in heart rate. Syndromes may occur as well including systemic gland involvement, ocular infection, and even meningitis, and/or sepsis. Diagnosis is based on serum samples Treatment immediate attention with antibiotic initiation with gentamicin or streptomycin.
Lyme disease is caused by spirochete bacteria Borrelia Burgdorferi carried in a tick. After 36 hours of attachment, the symptoms begin. Symptoms depend on stage as early localized, early disseminated, and late disease. In early localized, the hallmark symptom is erythema migrans, which is a red rash near tick bite. As it grows in size, a bull’s eye appearance may occur. Disseminated disease results in rashes that are often not proximal to tick bite. During this time of the infection, often arthralgias, myalgia, headaches, and fatigue result. Late disease manifests as continual symptoms after anti-biotic treatment. Diagnosis is based on clinical symptoms and serologic testing. Treatment and prevention entail anti-biotic therapy.
TICK BORNE RELAPSING FEVER
Soft-bodied tick transmitting Borrelia bacteria to humans occurs within 30 seconds. Symptoms include fever, myalgia, chills, arthralgia, nausea, and vomiting. Labs reveal hepatomegaly, splenomegaly, and thrombocytopenia. Often cranial nerve palsies result in most severe cases. Diagnsos is based on bacteria presence in the blood. Treatment includes anti-biotics such as penicillin, chloramphenicol, erythromycin, tetracyclines for 7-10 days.
SOUTHERN TICK-ASSOCIATED RASH ILLNESS
B. lonestari is the bacteria carried by lone star ticks causing the southern tick-associated rash illness. The illness is manifested as red lesions with central clearing and inconsistent borders as well as fatigue, headache, and myalgias. In comparison to Lyme Disease, this illness results in smaller lesions, more obvious central clearing, and faster recovery with treatment. Diagnosis is based on subjective complaints and objective physical examination. Treatment includes doxycycline. Currently, prevention entails tick avoidance.
COLORADO TICK FEVER
Colorado tick fever is result of either tick exposure or tick attachment. Clinically, the symptom include fever, headache, and myalgias. Often times, eye infection, retro-orbital pain, and photophobia occurs. Additional symptoms include macular, petechial, or maculopapular rashes, along with weakness and lethargy. Diagnostically, leuopenia, thrombocytopenia, and viremia are present. Treatment entails supportive therapy such as aspirin and fluids.
In conclusion, vector borne illnesses can be extremely severe. However, awareness around transmission and symptoms aids in understanding and thus optimizes treatment and prevention. Discuss with a healthcare professional for any other questions.
Pharm D, BCPS, BCACP, CDE, MSMTM