Vector borne diseases

Zeliha Kocak Tufan, MD, Assoc. Prof.

Infectious Diseases & Clinical Microbiology

Vectors

• Live carrier- transmits the infectious agent

• Insects-Athropods, ticks, flies…

CCHF

Sand fly fever

CDC

Chagas disease Life-threatening condition transmitted through triatomine bugs, contaminated food, infected blood transfusion. Trypanosoma cruzi

Chikungunya Viral disease transmitted to humans by infected mosquitoes (Aedes aegypti)

Dengue Fever Mosquito-borne infection that may cause lethal complications

Dracunculiasis Infection caused by drinking-water containing water fleas that have ingested Dracunculus larvae

Human African Trypanasomiasis Glossina-borne parasitic infection, fatal without prompt diagnosis and treatment

Leishmaniasis Infection is caused if bitten by female sandflies

Lymphatic filariasis Infection occurs when filarial parasites are transmitted to humans through mosquitoes

Lyme Disease Disease caused by infected ticks (Ixodes)

Malaria Disease caused by a parasite plasmodium, transmitted via infected mosquitoes

Yellow fever Viral disease transmitted via aedes mosquitoes

Onchocerciasis Parasitic disease caused by the filarial worm Onchocerca volvulus

MALARIA

• Anopheles

• Plasmodium falciparum, P. vivax, P. ovale and P. malariae

• Incubation: 10 days- 4 weeks (7 days-1 year)

• P. vivax and P. ovale—relapsing malaria–dormant in liver up to 4 years

CCHF

• Family: Bunyaviridae

• Type: Nairovirus

• Crimean-Congo hemorrhagic fever virus Mortality 5-30%

• Transmission: Tick bite (Hyalomma), contaminated blood exposure

• The virus is primarily transmitted to people from ticks and livestock animals.

• Human-to-human transmission can occur resulting from close contact with the blood, secretions, organs or other bodily fluids of infected persons.

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Hyalomma

• Incubation: 1- 13 days (9 days after tick bite)

• Fever, myalgia, fatique, head ache, bleeding

• Thrombocytopenia, leucopenia,

• Increased AST, ALT, CK, LDH

Petechia, echimosis

Gum bleeding

Hemoptysis

Hematemesis

Melena, Hematuria, nose bleeding, vaginal bleeding

Bleeding around/in visseral organs

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THERAPY

General suppotive care

Blood, erytrocyte, platelets, FFP

Ribavirin?

Prevention and control

• Reducing the risk of tick-to-human transmission: – wear protective clothing (long sleeves, long trousers); – wear light coloured clothing to allow easy detection of

ticks on the clothes; – use approved acaricides (chemicals intended to kill ticks)

on clothing; – use approved repellent on the skin and clothing; – regularly examine clothing and skin for ticks; if found,

remove them safely; – seek to eliminate or control tick infestations on animals

or in stables and barns; and – avoid areas where ticks are abundant and seasons when

they are most active. WHO 2013

• Reducing the risk of animal-to-human transmission: – wear gloves and other protective clothing while handling

animals or their tissues in endemic areas, notably during slaughtering, butchering and culling procedures in slaughterhouses or at home;

– quarantine animals before they enter slaughterhouses or routinely treat animals with pesticides two weeks prior to slaughter.

• Reducing the risk of human-to-human transmission in the community: – avoid close physical contact with CCHF-infected people; – wear gloves and protective equipment when taking care

of ill people; – wash hands regularly after caring for or visiting ill people.

WHO 2013

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West nile virus

• Family Flaviviridae

• Genus Flavivirus

• Mosquitoes are the principal vector of WNV.

• The virus has been isolated from more than 40 mosquito species, but the predominant genus is Culex.

• Wild birds are the principal host

• Humans and horses are accidental dead-end hosts.

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Şekil 1. Batı Nil Virüsü’nün yaşam döngüsü

(Pfeffer M, Dobler G. Emergence of zoonotic arboviruses by animal trade and migration. Parasit Vectors. 2010 Apr 8;3(1):35.)

Şekil 3. Batı Nil Virüs enfeksiyonunun klinik seyri

• About 1 in 5 people who are infected will develop a fever with other symptoms such as

– headache, body aches, joint pains, vomiting, diarrhea, or rash.

• Most people with this type of West Nile virus disease recover completely, but fatigue and weakness can last for weeks or months.

• The symptoms of neurologic illness can include headache, high fever, neck stiffness, disorientation, coma, tremors, seizures, or paralysis.

• People with certain medical conditions, such as cancer, diabetes, hypertension and kidney disease are also at greater risk for serious illness.

• Recovery from severe disease may take several weeks or months. Some of the neurologic effects may be permanent.

• About 10 percent of people who develop neurologic infection due to West Nile virus will die.

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• No vaccine or specific antiviral treatments for West Nile virus infection are available.

• Pain relievers can be used to reduce fever and relieve some symptoms

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LYME

Lyme disease is caused by the bacterium Borrelia burgdorferi and is transmitted to humans through the bite of infected blacklegged ticks (Ixodes)

Ticks can attach to any part of the human body but are often found in hard-to-see areas such as the groin, armpits, and scalp. In most cases, the tick must be attached for 36-48 hours or more before the Lyme disease bacterium can be transmitted.

Early localized stage (3-30 days post-tick bite) Red, expanding rash --- erythema migrans (EM) Fatigue, chills, fever, headache, muscle and joint aches, and swollen lymph nodes

Erythema migrans (EM)

or "bull's-eye" rash

•Rash occurs in approximately 70-80% of

infected persons and begins at the site of a

tick bite after a delay of 3-30 days (average is

about 7 days).

•Rash gradually expands over a period of

several days, and can reach up to 12 inches

(30 cm) across. Parts of the rash may clear

as it enlarges, resulting in a “bull's-eye”

appearance.

•EM lesions may appear on any area of the

body.

Early disseminated stage (days to weeks post-tick bite) Additional EM lesions in other areas of the body Facial or Bell's palsy (loss of muscle tone on one or both sides of the face) Severe headaches and neck stiffness due to meningitis Pain and swelling in the large joints (such as knees)

Bell's (facial) palsy

Loss of muscle tone on

one or both sides of the

face is called facial or

“Bell's” palsy.

Late disseminated stage (months to years post-tick bite) Approximately 60% of patients with untreated infection may begin to have intermittent bouts of arthritis, with severe joint pain and swelling. Up to 5% of untreated patients may develop chronic neurological complaints months to years after infection. These include shooting pains, numbness or tingling in the hands or feet, and problems with short-term memory.

Arthritis

Pain and swelling in the

large joints (such as

knees) can occur.

Dengue is a disease caused by any one of four closely related dengue viruses (DENV 1, DENV 2, DENV 3, or DENV 4).

The viruses are transmitted to humans by the bite of an infected mosquito.

• In the Western Hemisphere, the Aedes aegypti mosquito is the most important vector of dengue viruses.

• It is estimated that there are over 100 million cases of dengue worldwide each year.

• Fever, nausea, vomiting, rash

• Aches and pains

• Leukopenia

• Severe plasma leakage

• Impaired consciousness

• Failure of heart and other organs

• ……..

• Early recognition and prompt supportive treatment

Yellow fever

• Yellow fever virus is found in tropical and subtropical areas in South America and Africa.

• Acute viral haemorrhagic disease

• The virus is transmitted to humans by the bite of an infected mosquito Aedes Aegypti

• Vaccine is available

Map is from the following publication: Jentes ES. Poumerol G, Gershman MD, et al. The revised global yellow fever risk map and recommendations for vaccination, 2010: consensus of the Informal WHO Working Group on Geographic Risk for Yellow Fever. Lancet Infect Dis. 2011;11:622-32.

The "yellow" in the name refers to the jaundice that affects some patients. Up to 50% of severely affected persons without treatment will die from yellow fever. There are an estimated 200 000 cases of yellow fever, causing 30 000 deaths, worldwide each year, with 90% occurring in Africa.

WHO

There is no specific treatment for yellow fever. Treatment is symptomatic, aimed at reducing the symptoms for the comfort of the patient. Vaccination is the most important preventive measure against yellow fever. The vaccine is safe, affordable and highly effective, and a single dose of yellow fever vaccine is sufficient to confer sustained immunity and life-long protection against yellow fever disease and a booster dose of yellow fever vaccine is not needed. The vaccine provides effective immunity within 30 days for 99% of persons vaccinated.