Vector Borne Illnesses

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Vector Borne Illnesses

• By
• Bryan E. Mosora, DO

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Objectives

• Attendees will
• Recognize disease associated with the common
  vector involved
• Compare vector borne illnesses
• Demonstrate capability to council travelers to
  decrease risk of contracting a disease

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Uh Oh, What is this!
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What are they?

• African Trypanosomiasis
• Babesiosis
• Chagas Disease
• Dengue Fever
• Ehrlichiosi
• Leishmaniasis
• Lyme Disease
• Lymphatic Filariasis
• Trypanosomiasis
• Tularemia
• Typhus
• Malaria

• Onchocerciasis
• Plague
• Q Fever
• Relapsing Fever
• Rickettsia
• Rocky Mountain Spotted Fever
• Southern Tick-Associated Rash Illness
• Trachoma
• West Nile Virus
• Yellow Fever

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Vector Bone Diseases

• defined as the diseases, mostly parasitic, which
  are commonly transmitted through vectors.
• "Vector" is a term used broadly to refer to any
  animal that can transmit human disease or plays
  an essential role in the parasites life cycle.

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Be careful what you catch!!!!
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Real Problem for Us?

• According to the CDC, vector borne diseases are
  steadily on the rise.
• Due to ease of travel
• eco type vacation surge
• Lack of knowledge on patient and practitioners
  part.

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African trypanosomiasis

• also known as sleeping sickness
• protozoan parasites (two kinds specific to
  location) are both transmitted by the tsetse fly
• Diagnosis of the disease should correlate with
  appropriate history of exposure due to limited
  geographical predominance.

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African trypanosomiasis
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African trypanosomiasis

• A definitive diagnosis of infection requires the
  demonstration of the parasite, usually from the
  blood, lymph node aspirate or cerebrospinal fluid
  (CSF) on microscopy.
• Only research tools such as isoenzyme analysis
  and restriction fragment length polymorphism
  (RFLP) are available for a definitive subspecies
  identification.
• The organisms can be visualized in blood smears,
  lymph node aspirates, and CSF.

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African Trypanosomiasis
African Trypanosomiasis
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Tsetse Fly
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African trypanosomiasis

• Thick smears of peripheral blood stained with
  Giemsa or direct thin smear preparations may show
  trypanosomes
• sensitivity of blood smears varies with the stage
  of disease and the infecting species.
• Smears are more likely to be positive in early
  stages of infection when there are high numbers
  of circulating parasites

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Trypanosomiasis
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Trypanosoma brucei
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African trypanosomiasis

• All treatment regimens involve toxic or expensive
  drugs that are cumbersome to administer, and it
  is estimated that between three and five percent
  of those treated in the late stage of infection
  die from side effects of the treatment itself.
• Examination of the CSF is mandatory whenever the
  diagnosis is suspected, both to help confirm the
  diagnosis and to stage the infection.

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Treatment options

• Pentamidine
• Suramin
• Melarsoprol
• Eflornithine

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American trypanosomiasis

• AKA Chagas Disease
• caused by the protozoan parasite Trypanosoma
  cruzi
• The vector is the reduviid bug, also known as the
  "kissing bug".
• found only in Central and South America, Mexico
  and the southern United States.

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Kissing Bug
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Chagas' disease

• When the vector takes a blood meal, it defecates
  around the bite site.
• The resulting irritation causes the host to
  scratch
• Humans are characteristically bitten on the face
  at night while sleeping (kissing bug)
• inoculation of parasites can occur via breaks in
  the skin or directly into mucous membranes or
  into conjunctivae

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Chagas' disease

• The pathogenesis of chronic Chagas' disease is
  unclear.
• extensive debate over whether complications are
  due directly to parasite invasion or to secondary
  autoimmune mechanisms
• Organs involved in disease show chronic
  inflammatory changes and diffuse fibrosis.
• The conduction system and the muscle are affected
  in the heart.
• In the GI tract, loss of neurons, inflammation
  and fibrosis of the gut wall develop.

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Chagas' disease

• The major morbidity associated with this disease
  is threefold cardiac disease, megaesophagus, and
  megacolon.
• Cardiac involvement is characterized by
  myocarditis and ultimately a dilated
  cardiomyopathy that becomes evident years after
  infection.

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Chagas' disease

• Many individuals do not experience any symptoms
  and are unaware that they have been infected.
• The typical features of acute symptomatic
  infection are fever, swollen face or eyelids
  (Romana's sign), peripheral edema,
  conjunctivitis, hepatosplenomegaly, and
  lymphadenopathy.

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Romana's sign
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Megacolon
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Megaesophagus

• The most common symptom in megaesophagus is
  dysphagia.
• There can be associated discomfort and pain that
  typically starts in the lower substernal area and
  radiates superiorly.
• food may become lodged in the esophagus and cause
  local irritation, leading to inflammation,
  ulceration, bleeding, perforation and fistulas.
• Regurgitation of ingested food can also occur
• Patients with megaesophagus are at increased risk
  for esophageal cancer

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Megacolon

• Involvement of the colon leads to abnormal basal
  colonic motility and an impaired relaxation
  response in the anal sphincter.
• The typical presenting symptom is constipation.
  patients may go for weeks without being able to
  pass stool.
• Progressive colicky abdominal pain frequently
  develops.
• Physical examination often reveals a tympanitic
  abdomen and an easily palpable colon.
• Anorexia and malnutrition can also develop.

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Treatment

• The goals of medical care in those with Chagas
  disease are to eliminate the parasites
  (etiological treatment) and to correct the damage
  caused by the parasites.
• The only available drug with some activity
  against T cruzi that is tolerated in humans is
  benznidazole.
• The failure of treatment in the 30-40 of other
  patients may be related to parasite resistance to
  benznidazole, the intensity of parasitism, or
  other unknown reasons.
• The medical treatment of chronic heart chagasic
  disease is similar to that for other
  cardiomyopathies.

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Treatment

• Most patients, particularly those with
  ventricular tachycardia associated with
  myocardial dysfunction, may benefit from the use
  of class III antiarrhythmic drugs (sotalol and
  amiodarone).
• Patients in stages II and III of chagasic
  megaesophagus can be relieved by a dilatation of
  the esophagogastric sphincter using extensible
  balloons. surgical treatment is preferable.
• In chagasic megacolon, patients with moderate
  constipation or those in whom surgery is
  unsuitable may benefit from lubricant laxatives
  (paraffin oil) or drugs that stimulate colon
  mobility and a water-glycerol (101 ratio) enema.

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Malaria

• Human malaria is caused by four species of
  Plasmodia P. falciparum, P. vivax, P. ovale, and
  P. malariae.
• The majority of malaria infection is caused by
  either P. falciparum or P. vivax, and most
  malaria-associated deaths are due to P.
  falciparum
• Increased incidence over past several years

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Malaria

• Increasing resistance of malarial parasites to
  chemotherapy
• Increasing resistance of the Anopheles mosquito
  vector to insecticides
• Ecologic and climate changes
• Increased international travel to malaria-endemic
  areas

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Malaria
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Malaria

• Approximately 300 to 500 million cases of malaria
  and 700,000 to 2.7 million deaths occur annually
  worldwide
• Approximately 30,000 travelers from
  industrialized countries contract malaria each
  year

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Risk By Region

• Oceania 130 or higher
• Sub-Saharan Africa 150
• Indian subcontinent 1250
• Southeast Asia 11,000
• South America 12,500
• Central America 110,000

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Oceania
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Malaria

• During 2004, the Centers for Disease Control and
  Prevention received 1324 reports of cases of
  malaria in the United States, including four
  fatal cases
• Malaria transmission is predominantly via the
  bite of a female Anopheles sp. Mosquito
• Species of Anopheles mosquitoes are seasonally
  present in all states of the United States,
  except Hawaii
• In addition, "airport malaria" can occur when
  infected mosquitoes enter the country by aircraft
  and then transmit the infection.

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Malaria
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Malaria

• All four malaria parasite species digest red cell
  proteins and hemoglobin.
• The parasites derive energy from anaerobic
  glycolysis of glucose to lactic acid, which can
  cause hypoglycemia and lactic acidosis.
• The parasites also alter the red cell membrane,

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Malaria
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Malaria

• P. falciparum has additional unique
  characteristics that help to explain its distinct
  potential to cause severe or fatal disease.
• As falciparum parasites mature within red blood
  cells, they induce the formation of sticky knobs
  on the surface of erythrocytes
• results in obstruction to blood flow.

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Malaria

• The signs and symptoms of malaria are varied, but
  virtually all nonimmune individuals will
  experience fever.
• Other frequent symptoms include chills, sweats,
  headache, myalgias, fatigue, nausea, abdominal
  pain, vomiting, diarrhea and cough.
• .Early in malarial infections, especially with P.
  falciparum, febrile paroxysms often are daily and
  irregular.
• Anemia, thrombocytopenia, splenomegaly,
  hepatomegaly and jaundice can develop, and
  splenic rupture can occasionally occur

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Malaria

• The diagnosis of malaria should be considered in
  any febrile individual who has traveled to or
  resided in a malarious region, even if briefly or
  only in transit.
• Moreover, the diagnosis should be considered in
  others with fevers of unknown origin even if
  there is no known geographic exposure

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Malaria

• The conventional method for diagnosing malaria is
  light microscopy of a Giemsa-stained thick and/or
  thin blood smear
• Because of the cyclical nature of the
  parasitemia, smears should be taken every 6 to 12
  hours for 48 hours before the diagnosis of
  malaria is ruled out,
• first smear is positive in 95 percent of cases

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Malaria

• Travelers to malarious regions should receive
  from their physician or travel clinic advice
  about malaria
• Guidance on mosquito avoidance
• Prescriptions for appropriate chemoprophylactic
  medications
• Failure to comply with chemoprophylactic
  medication schedules can contribute to morbidity
  and death in travelers

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Malaria

• Mosquito avoidance
• Remaining in screened areas whenever possible
• Using mosquito netting, ideally treated with
  Covering exposed skin with clothing
• Applying insect repellent
• Clothing and bed netting can be treated with
  permethrin for protection against mosquitoes and
  ticks
• A number of drugs are available for use in
  malaria prevention, including chloroquine,
  metloquine, Malarone doxycycline, proguanil,
  primaquine, and Fansidar

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Malaria

• PROPHYLAXIS AGAINST CHLOROQUINE-RESISTANT
  FALCIPARUM MALARIA
• The incidence of chloroquine-resistant falciparum
  malaria varies according to the location visited.
• CDC website is updated frequently to highlight
  known resistance areas

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Lyme Disease

• Lyme disease is caused by the bacterium Borrellia
  burgdorferi and is transmitted to humans by the
  bite of infected blacklegged ticks.
• Typical symptoms include fever, headache,
  fatigue, and a characteristic skin rash called
  erythema migrans

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Tick
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Lyme disease
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Erythema Migrans
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Lyme Disease

• early disseminated Lyme disease, is when the
  infection of bacteria is beginning to spread and
  is affecting certain body functions.
• This stage occurs weeks to months after the bite
  of an infected tick.
• Numbness and pain in arms or legs
• Paralysis of facial muscles (usually on one side
  of the face)
• Meningitisfever, stiff neck, and severe
  headaches
• Abnormal heart beat (rare)

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Lyme Disease

• late (or chronic) Lyme disease can occur weeks,
  months, or even years after infection in patients
  who either never received antibiotic treatment
  for early Lyme disease or whose treatment did not
  kill all of the bacteria that cause Lyme disease.
  
• Chronic Lyme arthritis
• Nervous system problems, including memory loss
  and difficulty concentrating
• Chronic pain in muscles

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Lyme Disease

• Blood tests, also known as Lyme titers, cannot
  diagnose Lyme disease alone, but they are used to
  confirm a diagnosis.
• The most common blood test ordered for Lyme
  disease is the ELISA, with the western blot used
  as a follow-up test.
• Other bacterial infections and diseases may cause
  an ELISA to be positive
• the Western Blot, a more accurate test that can
  be used 6 to 12 weeks after infection and is
  recommended to confirm all positive or equivocal
  ELISA results.
• Treatment should be started if high clinical
  suspicion in light of the tests

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Treatment

• Oral antibiotics (eg, amoxicillin, doxycycline,
  cefuroxime axetil, erythromycin, azithromycin,
  amoxicillin-clavulanate) should be administered
  for 10-30 days with an average of 3 weeks
• Early disseminated disease findings may be
  treated with oral antibiotics for 21-30 days.
• meningitis or a high-degree heart block may be
  treated with intravenous ceftriaxone for 2-4
  weeks. Occasionally, prednisone may hasten
  resolution of the conduction defect
• Arthritis may be treated with oral antibiotics
  for 30-60 days, and intravenous ceftriaxone may
  be administered for coexistent neurologic
  disease.

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And in conclusion!!!!!

• Many other vector borne illnesses exist
• CDC maintains an extensive library of these
  illnesses and there common geographic localities
• Use resources such as the internet for quick info
  for patients who will be traveling to endemic
  areas

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Questions?????