Arboviruses, which progress clinically and subclinically in humans and whose numbers are increasing, constitute an important group of infectious diseases that are vectored by arthropods and are seen as syndromes in humans. In humans, it is mainly seen as syndromes characterized by encephalitis, short-lasting febrile illnesses, hemorrhagic fevers, polyarthritis and rash.
The fact that hemorrhagic fevers are used as biological weapons further increases their importance.
Crimean-Congo Hemorrhagic Fever (CCHF), which is in the hemorrhagic fever group of these syndromes, was seen in some of our provinces in the spring and summer of 2002 and 2003, and as a result of the studies carried out by the Ministry of Health, it was confirmed that the disease was CCHF.
CCHF is Bunyaviridae. It is a disease caused by viruses from the Nairovirus family, with a severe course and a very high fatality rate (approximately 30%; in some sources, this figure goes up to 50%). Although the disease is more common in animals than in humans, it is asymptomatic and is a zoonotic disease; It can also be seen in humans in the form of sporadic cases or epidemics.
This group of viruses are 100 nm (nanometer) sized, ribonucleic acid (RNA) containing, helical capsid and enveloped viruses.
CCF was first introduced. It was seen in Crimea in 1944 and was described as Crimean Hemorrhagic Fever. It was later realized that the disease seen in Congo in 1956 was the same as Crimean Hemorrhagic Fever in 1969, and the disease began to be known by its current name.
2. Clinical Description
Clinical symptoms occur as a result of liver and endothelial damage and a dramatic decrease in platelets.
Fever, malaise, headache, weakness, hypersensitivity, severe pain in the arms, legs and back. It begins with pain and a significant loss of appetite. Sometimes vomiting, abdominal pain or diarrhea may occur. In the first days, petechiae on the face and chest and redness in the conjunctiva are noticeable. Ecchymoses may occur on the trunk and extremities. Epistaxis, hematemesis, melena and hematuria are common. Sometimes vaginal bleeding may also occur. Hepatitis is often seen. 5th day of the disease in severe cases Hepatorenal and pulmonary insufficiencies may be observed starting from Fever occurs until the 5th or 12th day and subsides with lysis; The recovery period lasts a long time.
Death events can be seen mostly in the second weeks of the disease (5-14 days) and this rate can reach approximately 30%. Healing occurs on the ninth or tenth days of the disease.
Leukopenia and thrombocytopenia are particularly noteworthy as laboratory findings. The increase in Aspartate aminotransferase (AST), Alanine aminotransferase (ALT), Creatine kinase (CK) and bilirubin values is followed by the increase in alkaline phosphatase (ALP), Gamma glutamyltransferase (GGT) and Lactate dehydrogenase (LDH) values. Significant abnormalities are observed in prothrombin time (PT), activated partial prothrombin time (aPTT) and other coagulation tests. Even if there is no obvious bleeding, a decrease in hemoglobin levels may be observed.
3. Epidemiology and Transmission
The disease is often endemic in Africa, Asia, the Middle East and Eastern Europe. Sporadic cases and epidemics of CCHF have also been reported in Kosovo, Albania, Iran, Pakistan and South Africa in recent years.
The virus infects many domestic and wild animals and the disease is mild. While many birds are resistant to the virus, they play an important role in the spread of the virus. The disease in animals begins with the bite of infected ticks.
Although ticks belonging to the Hyalomassian family have a greater place in the transmission of CCHF, it is reported that 30 tick species can transmit this disease. The virus is maintained in ticks by transovarial and transstadial passages; It has also been reported that venereal transmission occurs between ticks. Immature ticks belonging to the Hyalomax family acquire viruses while sucking blood from small vertebrates and preserve them during their development stages. Ticks also transmit viruses while sucking blood from humans or animals.
Small vertebrates and especially ground-feeding birds constitute the most important host group that infects ticks; Ticks suck blood from these creatures at different stages of their biological evolution.
Ticks belonging to the Hyalomassian family have settled in a very wide geographical area, including our country. Our country has a geographically very suitable structure for ticks to survive. Although it varies depending on the species, ticks are small There is a wide spectrum of hosts, from small rodents and wild animals to domestic mammals and birds.
The disease can be seen mostly in those engaged in animal husbandry, slaughterhouse workers and those living in rural areas. Transmission may also occur through contact with the blood and tissues of infected animals. It is also reported that there is a risk of nosocomial infection.
While it is stated that immunity can last a lifetime after CCHF, for which there is no effective vaccine today, it is also stated that passive immunizations with convalescent period plasmas are not applicable.
4. Incubation Period
The incubation period following the acquisition of the virus by being bitten by a tick is generally 1-3 days; This period can be up to 9 days. In cases of contamination resulting from direct contact with infected blood, excreta or other tissues, this period is 5-6 days; The maximum period may be 13 days.
5. Diagnosis
For diagnosis, fully safe laboratories are needed in terms of biosafety. In diagnosis, isolation of the virus or virus RNA from blood and tissue samples and serological demonstration of virus antigen and antibodies against the virus are used. The antibodies formed can be detected by ELISA (Enzyme-Linked Immunosorbent Assay), the fastest serological method; IgG and IgM antibodies, which are immunoglobulins, can be detected in serum from approximately the 6th day of the disease. While IgMs can be detected in serum for up to 4 months, IgGs decrease; However, IgG antibodies may still be detected for up to 5 years.
In some people, the disease may not be diagnosed as it may result in death until specific antibodies are detected in the blood. In these cases, diagnosis can be made by virus isolation from blood and tissue samples, especially in the first 5 days of the disease. For this purpose, cell cultures, immunofluorescence method and EIA (Enzyme Immun Assay) can be used.
6. Treatment
Universal precautions (gloves, apron, glasses, mask, etc.) must be taken during contact with the patient and the patient's secretions. Generally, airborne transmission is not mentioned. However, contact with blood and body fluids should be avoided. In case of such contact, the contact must stay at least 14 days. It is necessary to monitor for fever and other symptoms for up to 10 days.
Necessary protective measures should also be taken during contact with animal blood, tissue or other animal body fluids.
>
Although tick control is very important, it seems quite difficult. Ticks can attack humans and suck blood in biological stages other than their egg stage. Both pasture ticks and house ticks must suck blood from their hosts in order to continue their development and continue their generation; In general, they do not show host specificity. Although it varies depending on geographical regions and species, ticks belonging to the Hyalomacaceae that transmit CCHF are generally active in April and October; This is the reason for the epidemics in these periods. For this reason, first of all, hosts should be kept away from ticks and ticks should be prevented from sucking blood.
Areas where ticks are found should be avoided as much as possible. If you are in animal shelters or areas where ticks can live, the body should be examined for ticks at regular intervals; Those that are not attached to the body should be carefully collected and killed, and the ticks that are attached should be removed without crushing them and without tearing off the mouth part of the tick (by moving it left and right with a pair of pliers, such as removing a nail).
One of the other important issues is to use the ticks near water and pastures for picnic purposes. Those who have been in places should check themselves for ticks when they return, and if there are ticks, they should be removed from the body in accordance with the procedure. Places with bushes, twigs and thick grass should be avoided, and such places should not be entered barefoot or with short clothes.
Workers working in forests and those who go hunting should wear rubber boots or tuck their trousers into socks to protect against ticks.
Animal owners should treat their animals with appropriate acaricides against ticks, animal shelters should be built in a way that does not allow ticks to survive, and cracks and crevices should be repaired and whitewashed. Animal shelters where ticks are found should be treated with appropriate acaricides as required.
Insect repellents, known as repellent, should be carefully treated to protect both humans and animals from tick infestations. available. Repellents are substances prepared in the form of liquid, lotion, cream, solid oil or aerosol and can be applied by applying to the skin or by absorbing into clothes. The same substances can be applied to the head or legs of animals; Additionally, plastic strips impregnated with these substances can be attached to the ears or horns of animals.
If ticks are abundant in the environment, they can be placed in areas suitable for ticks to live, such as pastures, meadows, bushes, twigs and lush grasses, without harming other creatures and the environment. , insecticide applications can be used. In cases where insecticide application to open areas is deemed appropriate, aircraft, helicopters, vehicles with mounted spraying devices or pumps carried on back should be used.
Tick control is carried out by the Ministry of Agriculture and Rural Affairs and the provincial and district organizations of this Ministry. It should be done in line with the recommendations and directives; It should not be forgotten that the problem can be solved if local governments and other relevant sectors approach the issue sensitively and give it the necessary importance.
- Over the decades, studies on the use of biological methods in controlling the tick population have also been carried out.
Read: 0
