Viral hemorrhagic fevers.pptx

Viral hemorrhagic fevers (VHFs

1. [email protected] [email protected] Dr.Azad A Haleem AL.Mezori FRCPCH,DCH, FIBMS Assistant Professor University Of Duhok College of Medicine Pediatrics Department Viral hemorrhagic fevers Scan For Contact

2. Introduction Viral hemorrhagic fevers (VHFs ) are a group of diseases that are caused by several distinct families of viruses. The term “ viral hemorrhagic fever ” refers to a condition that affects many organ systems of the body, damages the overall cardiovascular system, and reduces the body’s ability to function on its own. Symptoms of this type of condition can vary but often include bleeding , or hemorrhaging. Some VHFs cause relatively mild illness, while others can cause severe, life threatening disease.

3. Etiology Although VHFs are caused by several families of viruses, these viruses share some common characteristics: They are RNA viruses, These viruses are the most common cause of emerging disease in people because RNA viruses change over time at a high rate. They are covered, or enveloped , in a lipoprotein outer layer, making it easier to destroy these viruses with physical (heat, sunlight, gamma rays) and chemical (bleach, detergents, solvents) methods.

4. Etiology They naturally exist in animal or insect populations, referred to as  host populations , and are generally restricted to the geographical areas where the host species live. They spread to people when a person encounters an infected animal or insect host. After the initial spread into the human population, some VHF viruses can continue to spread from person-to-person. Outbreaks of VHFs in people can be difficult to prevent since they can occur sporadically and cannot be easily predicted.

5. VHF diseases by virus family : 1.Arenavirus  (order  Bunyavirales ) Chapare Hemorrhagic Fever (CHHF) Lassa Fever Lujo Hemorrhagic Fever (LUHF) 2.Flavivirus Alkhurma Hemorrhagic Fever (AHF) Kyasanur Forest Disease (KFD) Omsk Hemorrhagic Fever (OHF) Severe Dengue Yellow Fever 3.Filovirus Ebola Disease Marburg virus disease (MVD) 4.Hantavirus (order  Bunyavirales ) Hantavirus Hantavirus Pulmonary Syndrome (HPS) Hemorrhagic Fever with Renal Syndrome (HFRS) 5.Nairovirus (order  Bunyavirales ) Crimean-Congo Hemorrhagic Fever (CCHF) 6.Phenuivirus (order  Bunyavirales ) Rift Valley Fever (RVF)

6. VHF Challenges More of the world’s population is at risk for VHFs The number of viruses known to cause disease in humans around the globe is ever-increasing, and the way VHF viruses spread is likely to shift due to globalization, international travel, and climate change. Discovery and exploration of viruses and their hosts is necessary to limit global spread and disease burden.

7. VHF Challenges Person-to-person transmission of some VHFs can occur VHF viruses can spread to people when they come in contact with infected animals or insects. For many VHFs, person-to-person transmission can then continue, often through direct contact or in healthcare facilities without adequate infection control procedures.

8. VHF Challenges Confirmation of VHF cases can take time Underdeveloped laboratories cannot rapidly diagnose and confirm illnesses, leading to delays in isolating infected people. Fast and accurate diagnostics are vital during outbreaks to confirm VHF cases, leading to faster isolation of cases and ultimately shorter, less severe outbreaks. Improving VHF diagnostic techniques to make them faster, more accurate, and easier to produce and use is an essential component to controlling these diseases.

9. VHF Challenges Prevention of VHF outbreaks is difficult Outbreaks of VHFs occur sporadically and irregularly, and their occurrence can be difficult to predict. Prevention is more difficult when the animal host is unknown or challenging to control (such as rodents or ticks). Strong risk communication and health education efforts are required, focusing on exposure prevention for communities and infection control for healthcare providers.

10. VHF Challenges Availability of vaccines and treatments are limited With limited effective vaccinations or drug treatments available, some VHFs are treated only with basic medical care, which is not always adequate to prevent virus spread and save lives. It is important to understand how the virus infects and spreads within the body to help guide the development of treatments and new strategies to protect against infection.

11. Crimean-Congo hemorrhagic fever (CCHF) Crimean-Congo hemorrhagic fever (CCHF) is caused by infection with a tick-borne virus  ( Nairovirus )  in the family  Bunyaviridae . The disease was first characterized in the Crimea in 1944 and given the name Crimean hemorrhagic fever. It was then later recognized in 1969 as the cause of illness in the Congo, thus resulting in the current name of the disease.

12. Crimean-Congo hemorrhagic fever (CCHF) Crimean-Congo hemorrhagic fever is found in Eastern Europe, particularly in the former Soviet Union, throughout the Mediterranean, in northwestern China, central Asia, southern Europe, Africa, the Middle East , and the Indian subcontinent.

13. Transmission

14. Transmission Ixodid (hard) ticks , especially those of the genus,  Hyalomma , are both a reservoir and a vector for the CCHF virus. Numerous wild and domestic animals , such as cattle, goats, sheep and hares, serve as amplifying hosts for the virus. Transmission to humans occurs through contact with infected ticks or animal blood.

15. Transmission CCHF can be transmitted from one infected human to another by contact with infectious blood or body fluids. Documented spread of CCHF has also occurred in hospitals due to improper sterilization of medical equipment, reuse of injection needles, and contamination of medical supplies.

16. Clinical manifestations The onset of CCHF is sudden, with initial signs and symptoms including headache, high fever , back pain, joint pain, stomach pain, and vomiting. Red eyes, a flushed face, a red throat, and petechiae (red spots) on the palate are common. Symptoms may also include jaundice, and in severe cases, changes in mood and sensory perception. As the illness progresses, large areas of severe bruising , severe nosebleeds, and uncontrolled bleeding at injection sites can be seen, beginning on about the fourth day of illness and lasting for about two weeks.

17. Clinical manifestations In documented outbreaks of CCHF, fatality rates in hospitalized patients have ranged from 9% to as high as 50%. The long-term effects of CCHF infection have not been studied well enough in survivors to determine whether or not specific complications exist. However, recovery is slow.

18. Risk of Exposure Animal herders, livestock workers, and slaughterhouse workers in endemic areas are at risk of CCHF. Healthcare workers in endemic areas are at risk of infection through unprotected contact with infectious blood and body fluids. Individuals and international travelers with contact to livestock in endemic regions may also be exposed.

19. Diagnosis Laboratory tests that are used to diagnose CCHF include : antigen-capture enzyme-linked immunosorbent assay (ELISA), Real time polymerase chain reaction (RT-PCR), Virus isolation attempts, and detection of antibody by ELISA (IgG and IgM).

20. Diagnosis Laboratory diagnosis of a patient with a clinical history compatible with CCHF can be made during the acute phase of the disease by using the combination of detection of the viral antigen (ELISA antigen capture), viral RNA sequence (RT-PCR) in the blood or in tissues collected from a fatal case and virus isolation. Immunohistochemical staining can also show evidence of viral antigen in formalin-fixed tissues. Later in the course of the disease , in people surviving, antibodies can be found in the blood. But antigen, viral RNA and virus are no more present and detectable.

21. Treatment for CCHF is primarily supportive. Care should include careful attention to fluid balance and correction of electrolyte abnormalities, oxygenation and hemodynamic support, and appropriate treatment of secondary infections. The virus is sensitive in vitro to the antiviral drug ribavirin . It has been used in the treatment of CCHF patients reportedly with some benefit. Treatment

22. Prevention Agricultural workers and others working with animals should use insect repellent on exposed skin and clothing. Insect repellants containing DEET (N, N-diethyl-m-toluamide) are the most effective in warding off ticks. Wearing gloves and other protective clothing is recommended. Individuals should also avoid contact with the blood and body fluids of livestock or humans who show symptoms of infection. It is important for healthcare workers to use proper infection control precautions to prevent occupational exposure.

23. An inactivated, mouse-brain derived vaccine against CCHF has been developed and is used on a small scale in Eastern Europe. However, there is no safe and effective vaccine currently available for human use. Further research is needed to develop these potential vaccines as well as determine the efficacy of different treatment options including ribavirin and other antiviral drugs. Prevention