Haemorrhagic Fever PDF

Haemorrhagic fevers Prof. Ameer kadhim Hussein. M.B.Ch.B. FICMS (Community Medicine).  Objectives Describe and discuss the epidemiology, mode of transmission and preventive and control measures of Crimean-Congo haemorrhagic fever.  Haemorrhagic fevers Viral haemorrhagic fever...

Haemorrhagic fevers Prof. Ameer kadhim Hussein. M.B.Ch.B. FICMS (Community Medicine).  Objectives Describe and discuss the epidemiology, mode of transmission and preventive and control measures of Crimean-Congo haemorrhagic fever.  Haemorrhagic fevers Viral haemorrhagic fever is a term which usually applied to disease caused by : Arenaviridae (eg. Lassa fever). Bunyaviridae (eg. Crimean-Congo haemorrhagic fever). Filoviridae (eg. Ebola) Flaviviridae (eg. yellow fever).  Crimean-Congo haemorrhagic fever Crimean-Congo haemorrhagic fever (CCHF) is a widespread disease caused by a tick-borne virus (Nairovirus) of the Bunyaviridae family. The CCHF virus causes severe viral haemorrhagic fever outbreaks, with a case fatality rate of 10–40%. CCHF is endemic in Africa, the Balkans, the Middle East and some Asian countries. The hosts of the CCHF virus include a wide range of wild and domestic animals such as cattle, sheep and goats.  Crimean-Congo haemorrhagic fever Animals become infected by the bite of infected ticks and the virus remains in their bloodstream for about one week after infection, allowing the tick-animal-tick cycle to continue when another tick bites. Although a number of tick genera are capable of becoming infected with CCHF virus, ticks of the genus Hyalomma are the principal vector.  Transmission The CCHF virus is transmitted to people either by tick bites or through contact with infected animal blood or tissues during and immediately after slaughter. The majority of cases have occurred in people involved in the livestock industry, such as agricultural workers, slaughterhouse workers and veterinarians. Human-to-human transmission can occur resulting from close contact with the blood, secretions, organs or other bodily fluids of infected persons. Hospital-acquired infections can also occur due to improper sterilization of medical equipment, reuse of needles and contamination of medical supplies. Ixodid (hard) ticks, especially those of the genus, Hyalomma, are both a reservoir and a vector for the CCHF virus  Epidemiology of the disease CCHF is endemic in Africa, the Balkans, the Middle East and Asian countries south of the 50th parallel north – the geographical limit of the principal tick vector. Iraq is one of the eastern Mediterranean countries where CCHF is endemic. CCHF has been reported in Iraq since 1979 when the disease was first diagnosed in ten patients. Since then, six cases were reported between 1989 and 2009; 11 cases in 2010; three fatal cases were reported in 2018; and more recently 33 confirmed cases including 13 deaths (CFR 39%) were reported in 2021.  Crimean-Congo Hemorrhagic Fever – Iraq Between 1 January to 22 May 2022, the health authorities of the Republic of Iraq notified WHO of 212 cases of Crimean-Congo Hemorrhagic Fever (CCHF), of which 115 (54%) were suspected and 97 (46%) laboratory-confirmed; there were 27 deaths, 14 in suspected cases and 13 in laboratory confirmed cases. The number of cases reported in the first five months of 2022 is much higher than that reported in 2021, when 33 laboratory confirmed cases were recorded. Among confirmed cases, most had direct contact with animals, and were livestock breeders or butchers. Just over half of the confirmed cases were 15 to 44 years old (n=52; 54%) and of male gender (n=60; 62%). Figure 1. Distribution of laboratory confirmed cases of Crimean-Congo Hemorrhagic Fever by governorate, Iraq, 1 January to 22 May 2022 (n=97).  Incubation period The length of the incubation period depends on the mode of acquisition of the virus. Following infection by a tick bite, the incubation period is usually one to three days, with a maximum of nine days. The incubation period following contact with infected blood or tissues is usually five to six days, with a documented maximum of 13 days  Signs and symptoms Onset of symptoms is sudden, with fever, myalgia, dizziness, neck pain and stiffness, backache, headache, sore eyes and photophobia. There may be nausea, vomiting, diarrhoea, abdominal pain and sore throat early on, followed by sharp mood swings and confusion. After two to four days, the agitation may be replaced by sleepiness, depression and lassitude, and the abdominal pain may localize to the upper right quadrant, with detectable hepatomegaly.  Signs and symptoms Other clinical signs include tachycardia, lymphadenopathy and a petechial rash on internal mucosal surfaces, such as in the mouth and throat, and on the skin. The petechiae may give way to larger rashes called ecchymoses, and other haemorrhagic phenomena. There is usually evidence of hepatitis, and severely ill patients may experience rapid kidney deterioration, sudden liver failure or pulmonary failure after the fifth day of illness.  Signs and symptoms The mortality rate from CCHF is approximately 30%, with death occurring in the second week of illness. In patients who recover, improvement generally begins on the ninth or tenth day after the onset of illness. Crimean-Congo hemorrhagic fever virus infected patient develop a striking pattern of large ecchymoses which are not seen in other types of viral hemorrhagic fever Skin manifestations in an Iranian patient diagnosed as having CCHF presented with severe hemorrhagic form  Diagnosis CCHF virus infection can be diagnosed by several different laboratory tests: enzyme-linked immunosorbent assay (ELISA). antigen detection. serum neutralization. reverse transcriptase polymerase chain reaction (RT-PCR) assay. virus isolation by cell culture.  Treatment General supportive care with treatment of symptoms is the main approach to managing CCHF in people. The antiviral drug ribavirin has been used to treat CCHF infection with apparent benefit. Both oral and intravenous formulations seem to be effective.  Case Scenario A 37-year-old man presented hospital with a 5-day history of fever of 38.5°C, malaise, body ache, nausea, vomiting, and abdominal pain. Physical examination revealed mild tenderness on deep palpation in epigastrium and right hypochondriac region.  Case Scenario The patient also had hemorrhages, namely, hematuria, melena, gingival bleeding, and the most common manifestation was epistaxis. A chest X-ray showed bilateral lower and mid zone haziness with obliteration of costophrenic angles (picture of plural effusion). An ultrasound of the abdomen revealed some fluid collection. Portal vein cannot be visualized.  Case Scenario The patient’s condition deteriorated rapidly, and he was transferred to the intensive care unit, the repeated serology for CCHF came strongly positive after five days from the initial negative test. Accordingly, the patient was started on ribavirin and he responded to it very well. His condition improved dramatically. Prevention  Controlling CCHF in animals and ticks It is difficult to prevent or control CCHF infection in animals and ticks as the tick-animal- tick cycle usually goes unnoticed and the infection in domestic animals is usually not apparent. Furthermore, the tick vectors are numerous and widespread, so tick control with acaricides (chemicals intended to kill ticks) is only a realistic option for well-managed livestock production facilities. There are no vaccines available for use in animals.  Reducing the risk of infection in people Although an inactivated, mouse brain-derived vaccine against CCHF has been developed and used on a small scale in eastern Europe, there is currently no safe and effective vaccine widely available for human use. In the absence of a vaccine, the only way to reduce infection in people is by raising awareness of the risk factors and educating people about the measures they can take to reduce exposure to the virus. Public health advice should focus on several aspects  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  avoid areas where ticks are abundant and seasons when they are most active. 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 and butchering 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.  Community engagement and awareness Engage with communities to promote desired health practices and behaviours, including reduction of ticks exposure and safe meat preparation. Provide accurate and timely health advice and information on the disease.  Controlling infection in health-care settings  Health-care workers caring for patients with suspected or confirmed CCHF, or handling specimens from them, should implement standard infection control precautions. These include basic hand hygiene, use of personal protective equipment, safe injection practices and safe burial practices.  Samples taken from people with suspected CCHF should be handled by trained staff working in suitably equipped laboratories.