What are the diseases transmitted by mosquitoes ?
The list of diseases transmitted by mosquitoes is quite long.
These vector-borne diseases can be caused as much by viruses as by parasites, their consequences can be very serious, ranging from disability to death. In addition, there is often no specific medical treatment to cure these diseases. That’s why protecting yourself is so important.
Not sorry for the antivax, but when a preventive vaccine is available, it remains the best way to protect itself from its diseases and help stop their spread. There is nothing worse than a person who can’t be vaccinated, such as a young child or a pregnant woman, who falls ill because the mosquito who bit them became infected with another person who refused to vaccinate.
Reminder: To vaccinate is to protect oneself but also to protect weaker ones.
However, even if you have a preventive vaccine, you must protect yourself from mosquitoes that carry other diseases, for which you can use repellents, mosquito traps, impregnated clothes and mosquito nets.
We will answer his questions for each disease:
What are the symptoms ? What are the treatments ? How is it transmitted? Where is the disease present?
DENGUE
Dengue is characterized as a severe flu-like disease. In case of complications, it is called severe dengue. WHO estimated in 2017 that more than 2.5 billion people are now at risk of dengue, 100 million people are infected each year, 500 000 suffer from severe dengue and about 2.5% of those affected die.
This disease is caused by a Flaviviridae virus. In the world, there are 4 serotypes (variation of the virus) of dengue (DEN 1-4.
If you are infected by one of these stereotypes and recovery from it, you will have an immunity for this last the rest of your life. However, this immunity doesn’t protect you completely against the 3 others and being infected again by other dengue stereotypes increase the risk of severe dengue.
Symptoms
Symptoms can occur usually between 4 and 10 days after the bites of an infected mosquito.
- Fever (40°C/104°F)
- Severe headache
- Muscle pain
- Pain behind the eyes
- Nausea
- Vomiting
- Fatigue and rash.
- Swollen glands
The disease last for 2 to 7 days, but dengue can become severe and potentially deadly due to plasma leaking, fluid accumulation, respiratory distress, severe bleeding, or organ impairment.
Symptoms of severe Dengue
- Decrease in temperature (below 38°C/100°F)
- Severe abdominal pain
- Persistent vomiting
- Rapid breathing
- Bleeding gums
- Fatigue
- Restlessness
- Blood in vomit
Emergency medical care are needed as soon as possible. Indeed, death is possible within next 24-48 hours.
Treatment
A vaccine against dengue begins to be marketed by Sanofi Pasteur. The results of clinical studies conducted in Asia and Latin America seem encouraging.
However, this vaccine is initially intended for populations in endemic areas with higher risk. It is not yet a question that this vaccine constitutes a vaccination of the traveler.
Therefore treatments aim to relieve the symptoms and in cases of severe dengue, it is critical to maintain the patient’s body fluid volume.
Transmission
Dengue fever is present in more than in Asia, Africa, Europe and the Americas.
The mosquito that can carry the virus are :
- Aedes aegypti
- Aedes albopictus
When do they bite ? During the day especially at dawn and before dusk.
.
Distribution
MALARIA
Malaria is a caused by a parasite transmitted by the bites of female mosquitoes.
WHO estimated that in 2017, 219 million people were infected by malaria in 87 countries and 435 000 died from this disease.
There are 5 parasite species that cause malaria in humans.
The 2 most important are P. falciparum and P. vivax .
In contrast to diseases caused by viruses for which the sick cease to be a vector of the disease once cured, people infected with malaria remain for life and are new vectors of this disease.
Symptoms
The symptoms of Malaria may be mild and difficult to recognize as malaria. Furthermore, some adult can develop an partial immunity and never have the symptoms;
However, Malaria is a serious disease for young children pregnant women, people with HIV and non-immune people. For these populations, symptoms are stronger.
Symptoms can occur usually between 10 and 15 days after the bites of an infected mosquito.
• Fever (40°C/104°F)
• Headache
• chills
Children with severe malaria frequently develop one or more of the following symptoms:
– severe anaemia,
– respiratory distress
In adults, multi-organ failure is also frequent.
If not treated within 24 hours, P. falciparum malaria can progress to severe illness, often leading to death.A
Treatment
Malaria can be diagnosed using parasite-based diagnostic testing. The results of parasitological confirmation can be available in 30 minutes or less. Sooner the infection is detected, better are the chance of healing.
The best available treatment, particularly for P. falciparum malaria, is artemisinin-based combination therapy (ACT)
Up to now, there is no commercial vaccines against theses parasites, but one has been developed and is currently tested. It is called RTS,S/AS01, it targets P.faciparum and is destinated to young children. The vaccine has been introduced in 3 pilot countries – Ghana, Kenya and Malawi – in 2019.
Prevention treatment:
Different preventive treatment for Malaria can be found.
WHO– recommended preventive therapies include intermittent preventive treatment of pregnant women (IPTp), intermittent preventive treatment of infants (IPTi), and seasonal malaria chemoprevention (SMC). The objective of these interventions is to prevent malarial illness by maintaining therapeutic drug levels in the blood throughout the period of greatest malarial risk.
For travelers, 4 preventive treatments can be advised by a doctor depending on the country visited, the length of stay and the individual characteristics of each traveler. These treatments can be quite expensive, difficult to follow and can induce many side effects such as acute anxiety, depressive syndrome, agitation, mental confusion, suicidal tendencies or even minor disorders such as unexplained sadness, a headache, dizziness or sleep disturbance.
Transmission
The mosquito that can carry the parasite are Anopheles mosquitoes.
There are more than 400 different species of Anopheles mosquiton, around 30 are malaria vectors of major importance.
When do they bite ? During the day especially at dawn and before dusk.
Distribution
CHIKUNGUNYA
Discovered in 1952 in Africa, Chikungunya is an RNA virus transmitted by mosquitoes.
It takes its name from a word in Kimakonde language that means “to become contorted” in reference to one of the symptoms.
Symptoms
Symptoms can occur usually between 4 and 8 days ( a range from 2 to 12 days is also possible) after the bites.
- Fever
- Incapacitating joint pain.
- Muscle pain
- Headache
- Nausea
- Fatigue and rash.
The joint pain can last for month, thus the virus can cause acute, subacute or chronic disease.
Serious complications are not common but, in older people or young children, the disease can contribute to the cause of death.
Except joint pain, Chikungunya has the same symptoms as dengue fever, so it can be misdiagnosed. Furthermore, the symptoms can be mild and the infection may not be detected.
The presence of virus can ben confirm by serological tests as ELISA. The antobodies against the virus will be in high quantity after 3 to 5 weeks after the infection and will sta high 2-3 months.
Treatment
There is for the moment no vaccine for this virus but one is test phase and has good results.
Therefore treatments aim to relieve the symptoms with acetaminophen or paracetamol for the fever and a non-steroidal anti-inflammatory agent to relieve joint pain.
Transmission
Chikungunya is present in more than 60 countries in Asia, Africa, Europe and the Americas.
The mosquito that can carry the virus are :
- Aedes albopictus
- Aedes aegypti
- Other Aedes species
- Culex annulirostris,
- Mansonia uniformis
- Anopheles species
When do they bite ? During the day especially at dawn and late afternoon.
Distribution
ZIKA
Zika virus is flavivirus, discovered in Uganda in 1947 in monkeys and was later identified in humans in 1952 in Uganda and the United Republic of Tanzania.
Symptom
The symptoms appear at 3 to 12 days after the bite, but during this time the person can be the source of infection of other mosquitoes if it is stung again.
The majority of people infected with the virus (an estimated 70-80% of cases) do not develop any symptoms. In the rest of the population, the symptoms caused by the Zika virus are flu-like:
- Fatigue,
- Fever (not necessarily strong),
- Headaches,
- Muscle and joint pain in the limbs
- Conjunctivitis
- Pain behind the eyes
Zika virus infection during pregnancy can lead to severe complication as:
- Microcephaly
- Congenital abnormalities in the developing fetus and newborn.
- Fetal loss
- Stillbirth
- Preterm birth.
- Guillain-Barré syndrome
- Neuropathy and myelitis, particularly in adults and older children.
Treatment
Currently there is no vaccine to prevent infection with Zika virus, or specific medicine to cure the disease.
The treatment will consist in attenuating the painful symptoms, by taking analgesics.
Transmission
Aedes species, especially Aedes aegypti, are the major vector of Zika virus
When do they bite ? Along the day, peaking during dawn and dusk.
The virus can also be transmitted between humans by several ways:
- mother to fetus during pregnancy,
- sexual contact
- Blood transfusion
- organ transplantation
Distribution
YELLOW FEVER
200 000 people are infected by Yellow fever each year and 30 000 die from it. *
This disease is caused by a virus. Its name comes from the fact that some patient can develop jaundice, their skin turns to yellow.
Symptoms
When an infested mosquito bites you, the virus incubates in the body for 3 to 6 days.
Even if most of the time the yellow fever is asymptotic, the symptoms can be:
- Fever
- Muscle pain with prominent backache
- Headache
- Loss of appetite
- Nausea or vomiting
Normally they disappear in 3 or 4 days. However, some patient can suffer from a more sever yellow fever. Indeed, several hours after recovering from initial symptoms, high fever returns and several body systems are affected, usually the liver and the kidneys. News symptoms can occur:
- Jaundice
- Dark urine
- Abdominal pain with vomiting.
- Bleeding from the mouth, nose, eyes or stomach
.50% of the patients who enter the toxic phase die within 7 – 10 days.
Diagnosis
As the symptoms are common to other severe diseases, it can be difficult to confirm that patients is infected by yellow fever virus. The only way to be sure is to do some laboratory test like the ELISA test, to find antibodies against the virus.
Treatment
Once you are infected, there are no specific drugs against the virus. Only supportive treatment in hospitals, as soon as possible, can improve survival rates. The patient will be treated for dehydration, liver and kidney failure, and fever.
Therefore, preventive protection is the best way to not be infected.
It exists a Vaccine for the Yellow fever virus. It safe, affordable and a single dose provides life-long protection. The immunity is provided within 10 days for 80-100% of people vaccinated, and within 30 days for more than 99% of people vaccinated..
In accordance with the International Health Regulations (IHR), countries have the right to require travelers to provide a certificate of yellow fever vaccination.
Transmission
Haemagogus and Aedes mosquitoes are the vectors of this disease and can transmitted it to humans and monkeys.
Distribution
LYMPHATIC FILARIASIS
886 million people in 52 countries worldwide remain threatened by lymphatic filariasis and each year 120 million people were infected, with about 40 million disfigured and incapacitated by the disease.
The other name of this disease is elephantiasis, it is caused by a filarial parasite transmitted by mosquitoes to humans. It exists 3 types of these parasite worms : Wuchereria bancrofti, (90 % of the cases), Brugia malayi, Brugia timori.
The painful and profoundly disfiguring visible manifestations of the disease, lymphoedema, elephantiasis and scrotal swelling occur later in life and can lead to permanent disability. These patients are not only physically disabled, but suffer mental, social and financial losses contributing to stigma and poverty.
Symptoms
The parasites can live for approximately 6–8 years and produce millions of small larvae circulate in the blood, causing the disease and the transmission to other people.
Most of the time, the infections show no external but still cause damage to the lymphatic system and the kidneys, and alter the body’s immune system.
Lymphatic filariasis can become a chronic disease it leads to lymphoedema (tissue swelling) or elephantiasis (skin/tissue thickening) of limbs and hydrocele (scrotal swelling).
Furthermore, local inflammation involving skin, lymph nodes and lymphatic vessels often accompany the disease.
Patients are often left out of their societies and quickly get themselves in financial difficulty.
Treatment
Once infected you can get rid of the parasite. The best treatment is not be infected. Therefore, preventive treatment are existing and aim to stop the spreading of the disease
The medicines used have a limited effect on adult parasites but effectively reduce the density of microfilariae in the bloodstream and prevent the spread of parasites to mosquitoes.
The drugs used for this purpose are often albendazole, vermectin, diethylcarbamazine citrate (DEC). The combination of the three above show better results than alone.
People who are already infected by the worms and suffer from lymphoedema must have access to continuing care throughout their lives, both to manage the disease and to prevent progression to more advanced stages.
It is also possible to going through surgery for hydrocele.
Transmission
Lymphatic filariasis is transmitted by different types of mosquitoes for example by the Culex , Anopheles and Aedes mosquitoes.
Distribution
JAPANESE ENCEPHALITIS
This flavivirus causes 68 000 clinical cases every year, 30 % of theses cases can be fatal and 30-50% of the patients can suffer from permanent neurologic or psychiatric sequelae.
Symptom
Most of the time, the infection doesn’t show symptoms, but some people can develop the clinical phase after 4-14 days of incubation, this phase is characterized by an inflammation of the brain (encephalitis), the symptoms related to this inflammation are:
- Strong headache
- high fever
- disorientation,
- Coma
- Tremors
- Convulsions
A laboratory test is required in order to confirm with an ELISA test.
Treatment
There is no antiviral treatment, so treatments only focus on relieving symptoms and stabilize the patient.
Nevertheless, vaccines exist. Indeed, 4 types of Japanese encephaliyis can be found: : inactivated mouse brain-derived, inactivated Vero cell-derived, live attenuated, and live recombinant (chimeric). The vaccine use in your country will depend on its epidemic situation.
For traveler, normally the vaccine is inactivated and you have to take two doses with 28 days between the both.
Transmission
The virus is transmitted by the Culex species (mainly Culex tritaeniorhynchus).
Distribution
WEST NILE FEVER
Symptom
Often there are no symptoms. However, when they occur they are :
- Fever
- Headache
- body aches
- joint pains
- vomiting
- diarrhea
- rash
The complete recovery, with no more fatigue, can take weeks or months.
A little percentage of people can develop a severe illness affecting the central nervous system such as encephalitis (inflammation of the brain) or meningitis (inflammation of the membranes that surround the brain and spinal cord). 10% of these people can die.
Treatment
There are no vaccines to prevent or medications to treat WNV.
Some pain relievers can be used to reduce fever
In severe cases, patients often need to be hospitalized to receive supportive treatment, such as intravenous fluids, pain medication, and nursing care.
Transmission
West Nile virus is transmitted by mosquitoes, especially Culex species.
Distribution
Conclusion
Now, you know everything you need about diseases transmitted by mosquitoes !
You know what ? The best way to fight mosquitoes is that everyone knows our flying enemy and the vector-borne diseases in order to their stop spread !
Help the fight by liking our FB and sharing this article with everyone you know !
Like!! Really appreciate you sharing this blog post.Really thank you! Keep writing.