Vector-Borne Diseases
What are the vectors?
Vectors are organisms that transmit pathogens and parasites from an infected person (or animal) to another.
What are vector-borne diseases?
They are diseases caused by vectors, and are often found in tropical areas where insects are abundant and places where it is difficult to access safe drinking water and sanitation systems.
How serious is vector-borne disease?
Vector-borne diseases are among the most serious and unpredictable, and protection and control are extremely difficult since infection can return even after treatment because the organisms are inherent in the environment where they are spreading.
The seriousness of vectors lies in their ability to transmit the disease on a larger scale and faster than other diseases that require human-to-human contact to be transmitted. They also transmit the disease from different organisms (mice, rats, monkeys, birds, dogs, etc.) to the humans, and facilitate the spreading of the micro-organisms which cause serious diseases. The treatment of such diseases is difficult and protection requires the elimination of the vector.
Types of vector:
- Mosquitoes
- Flies (sand fly and black flies)
- Tick
- Bugs
- Snail carrying parasites
Possible places of presence of diseases vectors:
- Pots and ponds with stagnant water and swimming pools
- Rainwater gathering places such as parks' toys
- Abandoned places and equipment
- Open water tanks in the bathroom or kitchen
- Flower pots with stagnant water
- Rodent burrows and dark places
- Stagnant water due to air conditioning and ventilation holes
- Stagnant water on the roofs of buildings
- Swimming pools, ponds and swamps, especially in agricultural areas
- Animal husbandry sheds
- Beds and unclean sleeping areas may be a bunk.
Preventive measures to protect against vectors?
- Control insect vectors and the locations of their larvae by spraying with appropriate pesticides.
- Backfilling of ponds and marshes and disposal of waste and prevent accumulation.
- wearing long-sleeved clothes, covering the legs in places infested with insects, and applying insect repellents to the skin and clothing.
- Make sure to place mesh nets with tiny holes on all windows and doors to prevent insects from coming in.
- Use a mosquito net if you are planning to sleep outside.
- Cover water tanks tightly.
- Remove potential water-gathering areas such as old tires, planting basins and generally unused equipment.
- When you spend a long time out of the house, close the toilet cover, siphon cover, drainage holes and drains.
- Change the water in the flower pots every two days with cleaning the pots from the inside.
- Remove stagnant water in the drainage channels above the roof and in the garden.
- Change the water in the animal pots every two days.
- Avoid traveling to places where insect-borne diseases are as common as possible, and be sure to receive vaccines or medicines to prevent them in case of travel such as yellow fever or malaria.
- Sleeping places such as beds, bed linen and mattresses should be checked, especially in hotels, to avoid bugs.
- Pay attention to the cleanliness of the barns and the cattle where the breeding takes place.
- Dry the skin thoroughly after exposure to water in endemic areas.
- Do not swim in ponds or stagnant water, and do not defecate there at all.
- Control of snails carrying the infectious phase of schistosomiasis
- Always maintain personal hygiene and use pure water to drink or shower.
- Dispose of human waste away from water sources.
Vector-borne disease groups:
A. Mosquito-borne diseases
What is mosquito?
It is one of the most important insect vectors in humans, where it infects diseases due to transmission of viruses and parasites.
How does a mosquito transmit diseases?
When a mosquito carrying viruses, parasites or worms (microorganisms) which causes diseases bites a person, it transmits them into the body by injecting the microorganisms' saliva into the skin of a person.
It is possible to prevent the transmission of disease to another person by controlling mosquitoes, isolating people infected with the disease from healthy people or giving vaccines to healthy people when there is a risk of infection.
Main mosquito-borne diseases:
- Malaria
- Dengue Fever
- Yellow fever
- Chikungunya disease
- Elephantiasis
Prevention of Mosquito-borne diseases:
Infection with such diseases can be prevented by:
- Mosquito control.
- Take all possible measures to protect yourself from mosquito bites, such as wearing long-sleeved clothes, covering the legs in places infested with insects, and applying insect repellents to the skin and clothing.
- Make sure to place mesh nets with tiny holes on all windows and doors to prevent insects from coming in.
- Use a mosquito net if you are planning to sleep outside.
- Avoid traveling to places where insect-borne diseases are as common as possible, and be sure to receive vaccines or medicines to prevent them in case of travel such as yellow fever or malaria.
B. Fly-borne diseases
Types of flies carrying infectious diseases:
| The disease it causes | Description and whereabouts | Type of fly |
Leishmania | They feed on the blood and their ability to fly is weak and move by jumping from one victim to another. Their size is very small (3 mm) so it is difficult to find them before they start feeding on the victim, their bites cause severe pain that may last for several days. | Sand fly |
| River blindness | It is characterized by proliferation in running water such as small streams and rivers whose salivary fluids can cause a disease called black fly fever. It also transmits a nematode that lives within the human body for up to fifteen years, destroying the way the tissues of the internal organs, most notably the eyes; causing blindness | Black flies |
African trypanosomiasis | A two-wing African fly, carrying the parasite that causes African sleep sickness and transmitting it to humans through stings. It lives on the shores of lakes or river banks | Tsetse fly |
Tick-borne diseases
What is tick?
An insect that sucks the blood of animals and transmits diseases by transferring the blood it carries in its mouth from one creature to another. This insect may also absorb human blood if it is present in its environment. It is found in animal husbandry and forest barns.
Main tick-borne diseases:
- Lyme disease
- Crimean fever
Bug-borne diseases
What are bugs?
They are large nocturnal insects, which can be found in buildings with thatched roofs where they can hide in the daytime. Although they are large, their bites are painless, but they leave their contaminated stools near the opening of the wound.
Main Bug-borne diseases
Chagas disease
What is Chagas disease?
This disease occurs as a result of the transmission of trypanosomiasis Crozi (Trypanosomacruzi) to humans through the bug insect, known by several names, including "kissing bugs" and bug insects bite lips or face and usually leave behind feces contaminated with this parasite.
Where is Chagas disease spread?
- The disease spreads in rural areas, especially in houses with thatched roofs, and bugs hide during the day in the cracks of walls and ceilings, mud and brick milk, and feed on human blood.
- Predominantly in Mexico, Central America or South America.
What are the symptoms of the disease?
There are two phases of Chagas disease:
Acute phase:
The acute phase lasts several weeks or months after infection, is rarely fatal, and symptoms are mild and may not be noticed, including:
- Fever and body aches
- swelling of the eyelid
- Swelling at the bite site
- Swelling of the of the acute phase often go away without treatment, but the infection does not go away, and the infection continues if untreated and can develop into the chronic phase.
Chronic phase:
Chronic phase may be more serious, and symptoms may appear up to 10-20 years after infection, including:
- Irregular heartbeats.
- Cardiac hypertrophy
- Problems with digestion and bowel movement.
- Increased chance of stroke.
What is the treatment of Chagas disease?
Treatment of Chagas disease depends on the elimination of the parasite and the treatment of symptoms associated with the infection.
In the acute phase, treatment with antiparasitic drugs can be used. In the chronic phase, treatment is limited to symptomatic treatment.
How can Chagas disease be prevented?
- Avoid sleeping in mud and straw houses, as these types of housing are more likely to house triatomine bugs.
- Use insecticides to remove insects from the place of residence.
- Insect repellent products can be sprayed on beds to eliminate bedbugs
Diseases transmitted by helminths
The most important diseases transmitted by snails:
Bilharzia
What is bilharzia?
It is a disease caused by parasitic worms.
How can you get the disease?
Infection occurs when the skin is exposed to fresh water containing snails that transmit worms.
Fresh water becomes contaminated with schistosomiasis eggs when infected people urinate or defecate in those waters, where eggs hatch and worms and infect appear certain types of snail snails found in fresh water to grow and multiply within the shell. T he parasite then leaves the snails and moves to the surrounding water where it can survive for 48 hours.
Within several weeks, helminths mature and become adult, remaining in the blood vessels where females produce eggs. Some eggs move into the bladder or intestines and then come out with urine or stool.
What are the symptoms of Bilharzia?
- Within days of infection, you may develop a rash or itching.
- Fever, chills, cough, muscle pain can appear within one to two months of infection.
- In adult worms, eggs move to the intestines, liver, or bladder causing inflammations or scars.
- Children who develop frequent schistosomiasis may experience anemia and learning difficulties.
- Liver, intestinal, lungs and bladder damage may occur years after infection.
How can cases of schistosomiasis be diagnosed?
Blood, urine or stool samples are taken to detect the presence of parasites, and the results usually appear 6-8 weeks after exposure to contaminated water.
What is the treatment for schistosomiasis?
There are safe and effective medications in the treatment of schistosomiasis, including praziquantel, a drug that is usually recommended to use, and should consult a doctor for diagnosis and treatment.
What are the risk factors?
People present or traveling to areas where schistosomiasis has spread and their skin has been exposed to fresh water in rivers, lakes, streams and lakes are at risk.
Prevention:
- Dry the skin thoroughly after exposure to water in endemic areas.
- Do not swim in ponds or stagnant water, and do not defecate there at all.
- Control of snails carrying the infectious phase of schistosomiasis
- Always maintain personal hygiene and use pure water to drink or shower.
- Dispose of human waste away from water sources.
- Bath water should be heated to a boiling point for at least 1 minute. Water stored in reservoirs for at least two days is usually safe.
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