Symptoms
Questing behaviour itself does not produce symptoms in the host. Symptoms arise from the diseases transmitted by the vectors (ticks, mites) while they are questing and subsequently feeding. These symptoms vary drastically depending on the specific disease transmitted. Some examples include:
Lyme disease (transmitted by ticks): Fever, headache, fatigue, characteristic "bulls-eye" rash (erythema migrans).
Rocky Mountain Spotted Fever (transmitted by ticks): Fever, headache, rash (often starting on wrists and ankles).
Ehrlichiosis (transmitted by ticks): Fever, headache, muscle aches, fatigue.
Anaplasmosis (transmitted by ticks): Fever, headache, chills, muscle aches.
Babesiosis (transmitted by ticks): Fever, chills, fatigue, hemolytic anemia.
Scrub typhus (transmitted by mites): Eschar (a dark, crusty ulcer at the site of the bite), fever, headache, rash.
Causes
The cause of questing behaviour is the inherent survival strategy of ticks and mites to find a blood meal, which is essential for their life cycle, including molting, reproduction, and survival. The presence of specific pathogens within the vector (e.g., Lyme disease bacteria in a tick) is a separate cause that contributes to the potential for disease transmission during questing. Questing behavior is driven by:
Hunger: The primary motivation is to obtain a blood meal.
Environmental Cues: Ticks and mites use environmental cues (temperature, humidity, CO2 gradients, vibrations) to determine when and where to quest.
Life Cycle Stage: Questing is most prevalent during specific life stages (e.g., larval and nymphal stages of ticks).
Host Availability: Areas with high host populations (e.g., deer, rodents) will have higher tick densities and questing activity.
Medicine Used
Treatment focuses on addressing the specific disease transmitted by the vector, not the questing behavior itself. Common medications include:
Bacterial Infections (Lyme disease, Rocky Mountain Spotted Fever, Ehrlichiosis, Anaplasmosis): Antibiotics (e.g., doxycycline, amoxicillin, ceftriaxone, tetracycline). The specific antibiotic and duration of treatment depend on the disease and severity.
Parasitic Infections (Babesiosis): Antiparasitic drugs (e.g., atovaquone and azithromycin, quinine and clindamycin).
Scrub Typhus: Antibiotics such as doxycycline. Symptomatic treatment (e.g., pain relievers, fever reducers) may also be used.
Is Communicable
The diseases transmitted by questing vectors (ticks, mites) are generally not communicable directly from person to person. They are transmitted via the bite of an infected vector. An exception may exist for some very rare tick-borne diseases through blood transfusions or from mother to fetus during pregnancy, but these are not typical routes of transmission.
Precautions
Preventing tick and mite bites is the primary precaution. This includes:
Avoidance: Stay on cleared trails, avoid walking through tall grass or wooded areas.
Protective Clothing: Wear long pants, long-sleeved shirts, tuck pants into socks or boots.
Repellents: Use insect repellents containing DEET, picaridin, or permethrin (on clothing).
Tick Checks: Thoroughly check yourself, your children, and your pets for ticks after being outdoors. Pay close attention to areas like the groin, armpits, scalp, and behind the ears.
Tick Removal: If you find a tick, remove it promptly and carefully using fine-tipped tweezers. Grasp the tick as close to the skin as possible and pull upward with steady, even pressure. Do not twist or jerk the tick.
Landscaping: Keep grass mowed, remove leaf litter, and create a barrier of wood chips or gravel between lawns and wooded areas.
Animal Control: Consider measures to control tick populations on pets (tick collars, topical treatments) and in your yard.
How long does an outbreak last?
The duration of an outbreak of a tick- or mite-borne disease depends on several factors, including:
Vector Population: The density of the tick or mite population in a given area.
Environmental Conditions: Temperature, humidity, and rainfall can affect vector survival and activity.
Host Availability: The presence of reservoir hosts (e.g., rodents, deer) that maintain the pathogen in the environment.
Public Awareness and Control Measures: Public health interventions, such as education campaigns and vector control programs, can help to shorten outbreaks. Outbreaks can last for weeks to months, often coinciding with the peak activity seasons of the vectors (spring, summer, and fall). The overall duration varies geographically and from year to year.
How is it diagnosed?
Diagnosis of diseases transmitted by questing vectors typically involves:
Medical History and Physical Examination: The doctor will ask about your symptoms, recent travel history, and any potential exposure to ticks or mites.
Blood Tests:
Antibody Tests: Detect antibodies to the pathogen in your blood. These tests may take several weeks to become positive after infection. Examples: ELISA, Western blot (for Lyme disease).
PCR (Polymerase Chain Reaction): Detects the pathogen's DNA in your blood. This can be useful in the early stages of infection.
Blood Smear: To identify parasites in the blood (e.g., for Babesiosis).
Clinical Presentation: Considering the combination of symptoms, physical findings, and laboratory results to make a diagnosis. It is important to note that some tests can have false-negative results, especially early in the infection.
Timeline of Symptoms
The timeline of symptoms varies depending on the specific disease transmitted. Here are some general examples:
Lyme Disease:
Early Localized Lyme Disease (Days to Weeks): Erythema migrans rash (bulls-eye rash) at the site of the tick bite, fatigue, headache, muscle aches, fever.
Early Disseminated Lyme Disease (Weeks to Months): Multiple erythema migrans rashes, facial palsy (Bell's palsy), arthritis, heart problems (e.g., Lyme carditis).
Late Lyme Disease (Months to Years): Chronic arthritis, neurological problems (e.g., cognitive impairment, neuropathy).
Rocky Mountain Spotted Fever:
Days 2-14 After Tick Bite: Fever, headache, muscle aches, nausea, vomiting.
Days 2-5 After Fever: Rash typically starting on wrists and ankles, then spreading to the trunk.
Ehrlichiosis/Anaplasmosis:
5-14 Days After Tick Bite: Fever, headache, muscle aches, chills, nausea, vomiting.
Babesiosis:
1-4 Weeks After Tick Bite: Fever, chills, fatigue, headache, muscle aches, hemolytic anemia.
Scrub typhus:
6-21 Days After Bite: Eschar at bite site, fever, headache, rash, muscle pain, cough, and gastrointestinal symptoms. It's crucial to remember that the onset and severity of symptoms can vary greatly from person to person.
Important Considerations
Early Diagnosis and Treatment: Prompt diagnosis and treatment are essential for preventing serious complications of tick- and mite-borne diseases.
Co-infections: Ticks can transmit multiple pathogens in a single bite, leading to co-infections, which can complicate diagnosis and treatment.
Geographic Distribution: The prevalence of different tick- and mite-borne diseases varies geographically. Awareness of the diseases common in your area is important.
Prevention is Key: The best way to prevent these diseases is to avoid tick and mite bites.
Consult a Healthcare Professional: If you experience symptoms after a tick or mite bite, seek medical attention promptly.
Climate Change: Climate change is impacting the distribution and activity of tick and mite populations, potentially leading to increased risk of disease transmission in some areas.
Emerging Diseases: New tick- and mite-borne diseases are being discovered, highlighting the need for ongoing research and surveillance.