Viral Haemorrhagic Fevers Craig Corcoran NHLS Virology, Groote Schuur Hospital

VHF- what is it all about? VHF’s attract the attention of medical professionals and the general public for a variety of reasons They are high on the public mind as they are thought of as highly infectious, killing their victims in a dramatic way Mysteries remain as to the source of some of them

“Viral Haemorrhagic Fever” An acute febrile illness characterized by malaise, myalgia, and prostration dominated by generalized abnormalities of vascular permeability, and regulation. Bleeding manifestations often occur, particularly in severe cases; they are usually diffuse and reflect widespread vascular damage rather than life- threatening volume loss.

Filoviridae (Ebola, Marburg) Arenaviridae (Lassa, Junin, Machupo, Guanarito) Bunyaviridae (CCHF, RVF, Hantaviruses) Viral Haemorrhagic Fevers Flaviviridae (dengue, yellow fever, TBE encephalitides) Enveloped RNA viruses

These viruses share a number of features: They are all RNA viruses and are enveloped (i.e covered in a fatty (lipid) coating Their survival is dependent on an animal or insect host called the natural reservoir They are geographically restricted to areas where their host species live Humans are not the natural reservoir for any of these viruses. Humans are infected when they come into contact with infected hosts, and with some viruses, can transmit the virus to one another Human outbreaks occur sporadically and irregularly. These outbreaks cannot be easily predicted With few exceptions, there is no cure or established drug treatment for VHFs

VHF and other infectious diseases travel quickly nowadays

Early clinical signs and symptoms may be very discrete and cannot easily be distinguished from those of other illnesses

Clinical signs and symptoms are easier to interpret once the disease has progressed already

VHF-clinical picture Short incubation period Non-specific onset of illness Headache, myalgia, arthralgia Pharyngitis, conjunctival injection/bleed GIT discomfort/disturbances Impaired consciousness Haemorrhages Proteinuria Jaundice Rash, exanthema

VHF-differential diagnosis VHF vs. VHF: –clinical picture-unreliable, epidemiology-approximate, laboratory- proof VHF vs. bacterial infections –Typhoid, leptospirosis, tick-bite fever, shigellosis, purulent pharyngitis, sepsis (streptococcal, staphylococcal, meningococcal), plague VHF vs. parasitic diseases –Malaria, african trypanosomiasis, amoebiasis VHF vs. viral diseases –Viral hepatitis, herpes simplex

Dengue fever Main hosts- non human primates Human-to-human transmission through Aedes spp. 2.5 billion individuals at risk million infected each year with thousands of deaths

Dengue-clinical features Fever, headache, back pain, chills, musculoskeletal pain, rash, leucopaenia, thrombocytopaenia Usually lasts 4-10 days Dengue haemorrhagic fever/Dengue shock syndrome –Acute vascular hyperpermeability plus abnormal haemostasis –Rapid deterioration after 2-5 days –Scattered petechiae, ecchymoses, easy bruising/bleeding, hepatomegaly, epigastric pain Pathogenesis: enhancing antibodies- maternal in infants, second infection with a different serotype Supportive treatment, vaccine in development

dengue tourniquet test DHF

Yellow Fever Historic illness stretching back 400 years yellow: jaundice affecting certain patients Mosquitos (Aedes and haemogogus) are the true reservoir and vector Estimated cases/year, deaths Symptoms vary from mild to severe with haemorrhagic manifestations Africa and South America only

‘acute’ phase- fever, headache, muscle pain, GIT disturbance 15% enter a ‘toxic’ phase and rapidly develop jaundice with bleeding manifestations and renal failure. 50% die within days Supportive treatment Prevention: vaccine- 17D live attenuated, safe and highly effective

Filoviruses: Ebola HF Simultaneous large outbreaks in Yambuku (Zaire, now DRC) and Nzara/Maridi (Sudan) Originally thought to be one outbreak Virology now recognises 2 distinct viruses EBO-Z: 318 cases; 88% fatal EBO-S: 284 cases; 53% fatal

1979, , 1996, , * , 1979, 2004 *Doctor returning from Gabon Ebola Outbreaks Congo 2003

Filoviruses: Marburg HF 1967: Marburg, Frankfurt & Belgrade –African green monkeys from Uganda 25 primary 6 secondary –1 sexual transmission from husband to wife 85 days after onset of illness, virus cultured from semen 7 deaths

Marburg outbreaks

Routes of transmission: filoviruses Contact with body fluids of an ill patient –HCW and relatives Infected carcasses (handling/cutting of dead primates) Needle transfer Preparation of body for burial Sexual transmission Laboratory accident Aerosol infectivity potential demonstrated experimentally in monkeys (Ebola)

Reservoir of infection Not identified in terrestrial animals or in insects Non-human primates suffer but are not the reservoir Association with caves and mines make bats suspects for Marburg Fruit bats- ? reservoir for Ebola and Marburg (antibodies and RNA found by researchers in Gabon)

Filoviruses: clinical presentation 1-2 week incubation Abrupt onset fever, headache, myalgia Non-pruritic papular erythematous eruption becoming large coalescing macules and papules Palatal petechiae and haemorrhages GI symptoms, chest pain, delirium Sever cases- haemorrhages from venipuncture sites, mucous membranes and venipuncture sites 53-88% case-fatality ~ 45% hemorrhage Supportive treatment Vaccines in development

Marburg blanching maculopapular rash, day 5, Johannesburg 1975

Marburg 2005: 335 cases, 283 deaths

Arenaviridae Arenaviruses associated with human disease VirusOrigin of NameYear Distribution LassaTown, Nigeria 1969West Africa JuninTown, Argentina1957South America MachupoRiver, Bolivia 1962South America GuanaritoArea, Venezuela1989South America SabiaTown, Brazil1990South America LCMVClinical disease1933Worldwide Arenaviruses associated with human disease VirusOrigin of NameYear Distribution LassaTown, Nigeria 1969West Africa JuninTown, Argentina1957South America MachupoRiver, Bolivia 1962South America GuanaritoArea, Venezuela1989South America SabiaTown, Brazil1990South America LCMVClinical disease1933Worldwide

Lassa: general facts Viral hemorrhagic fever caused by the Arenavirus Lassa Transmitted from rodents to humans Discovered in Nigeria, 1969 Endemic in portions of West Africa Seasonal clustering: Late rainy and early dry season Affects all age groups and both sexes

Lassa virus “arenosus” (Latin “sandy”)

Endemic in areas of West Africa, including Nigeria, Liberia, Sierra Leone, and Guinea Estimated 300, ,000 infections/year, with 5000 deaths Rodent-to-human transmission (the “multimammate rat”, Mastomys species-complex) Secondary human-to-human transmission with the potential for nosocomial outbreaks with high case-fatality

Rodent reservoir Mastomys species complex

Lassa: Transmission Rodent-to-human: –Inhalation of aerosolized virus –Ingestion of food or materials contaminated by infected rodent excreta –Catching and preparing Mastomys as a food source

Lassa: Transmission Human-to-human: –Direct contact with blood, tissues, secretions or excretions of infected humans –Needlestick or cut –Inhalation of aerosolized virus –Sex –Breast feeding

Lassa: Clinical Aspects 80% asymptomatic Incubation period of 5-21 days Gradual onset of fever, headache, malaise and other non-specific signs and symptoms Pharyngitis, myalgias, retro-sternal pain, cough and gastrointestinal symptoms typically seen A minority present with classic symptoms of bleeding, neck/facial swelling and shock Case fatality of hospitalized cases: 15-20% Particularly severe in pregnant women and their offspring Deafness a common sequela

Lassa: Treatment Supportive measures Ribavirin –Guanosine nucleoside analog: blocks viral replication by inhibiting IMP dehydrogenase –Licensed for treatment of RSV and HCV –Potential adverse effects: Dose dependent reversible anemia Pancreatitis Teratogen in rodents

Crimean-Congo Haemorrhagic Fever

CCHF-some background Crimean peninsula- Crimean haemorrhagic fever (about 200 cases) Belgian Congo- 1 child- Congo Fever Virus isolated in suckling mice in cases diagnosed annually in South Africa Case fatality rate 20-25%, 30-50% without proper medical attention Mid 1980’s- nosocomial outbreak at TBH- 8 cases, 2 deaths 27 cases October Oudtshoorn ostrich abattoir workers

Distribution of CCHF virus

Distribution of the bont-legged ticks in South Africa reservoir and vector Hyalomma marginatum rufipes Hyalomma marginatum turanicum Hyalomma truncatum

Hyalommas are two host ticks - Lavae and nymphs feed on the first host - Adults feed on the second host -Cattle -Sheep -Goats -Ostriches

So when are humans at risk? Bitten by tick/s or crushed tick/s with bare hands Direct contact with fresh blood or other tissues of livestock or game animals (ear tagging, castration ect.) Direct contact with blood, secretions or excretions of a confirmed or suspected CCHF patient including needlestick injuries Resided in or visited a rural environment where contact with livestock or ticks was possible but a specific incident constituting exposure cannot be identified NB- incubation period usually 2-7 days hence exposure usually < 7days

What are the clinical features? Sudden onset Fever ≥ 38ºC on at least one occasion Severe headache Myalgia Nausea and/or vomiting Pharyngitis, conjunctivitis Bleeding tendency: petechial rash, ecchymoses, epistaxis, haematemesis, haematuria or melaena

Skin petechiae

Petechial haemorrhages on the palate

Large ecchymoses

CCHF- laboratory findings Leukopaenia or leukocytosis –WCC< 3 x 10 9 /l or ≥ 9 x 10 9 /l Thrombocytopaenia –Platelet < 150 x 10 9 /l –Usually < 100 x 10 9 /l Abnormal INR and APTT Transaminitis –AST ≥ 100iu/l –ALT ≥ 100iu/l

CCHF-differential diagnosis Malaria, tick bite fever, disseminated HSV, viral hepatitis, typhoid, rift valley fever, anthrax, brucellosis, Q fever… History of exposure, incubation period following exposure, signs and symptoms, laboratory findings

viremia 5 IgM RT-PCR ELISA IgM IgG IFA CCHF : viral/antibody kinetics Viral isolation 010 IgG 16 IgM duration: 2-3 months up to 6 months…

NICD, Johannesburg, BSL-4 (3) Viral detection: (blood specimen) –RT-PCR (nested) –Cell culture (Vero E6 cells) –Innoculation of newborn mice Antibody detection : (serum sample) -IFA -ELISA -NT CCHF : laboratory diagnosis

Specific management Supportive: monitoring of vital functions blood, fluid replacement treatment of DIC Specific: Ribavirin ?? Immune plasma Isolation and barrier nursing

PREVENTION OF CCHF Ticks most active during Dec, Jan, Feb, March- avoid hiking/camping DEET repellents for skin Permethrin repellents for clothing – (0.5% permethrin should be applied to clothing ONLY) Check for and remove ticks at least twice daily. If a tick attaches, do not injure or rupture the tick. Remove ticks by grasping mouthparts at the skin surface using forceps and apply steady traction.

PREVENTION OF CCHF Persons working with livestock- wear gloves and other protective clothing to prevent skin contact with infected tissue or blood Quarantine and treatment with an ascaricide prior to slaughter (ostriches)

Infection Control

Handling laboratory specimens from patients with suspected or confirmed VHF-non viral diagnostic specimens Common sense- know the risks Blood and other specimens are highly infectious Risk of transmission through skin/mucous membrane contact and needle stick injuries. ?? Respiratory transmission but avoid aerosolisation of specimens Limit laboratory testing to what is strictly necessary and where possible run specimens at a time when there is minimal disruption to routine work

Useful to for two techs to work together- one to process the specimen, other to operate the instrument Protective clothing: disposable gown, 2 pairs of gloves, mask and eye protection Centrifuge with closed buckets and decontaminate after use Open buckets, specimens and load instrument racks in a BSL-2 cabinet Discard residual sample and sampling containers into 2% glutaraldehyde or sodium hypochlorite Decontaminate instruments according to manufacturers instructions Clean BSL-2 cabinet with glutaraldehyde or sodium hypochlorite Discard protective clothing, gloves, specimens, ect. Into a biohazard labelled autoclave bag. Double bag and send for autoclaving

Haematology: –prepare slides in a BSL-2 cabinet, once fixed regard as non-infectious –Regard air dried slides as infectious, decontaminate microscope after use Microbiology: –protective clothing, process specimens in BSL-2 cabinet, discard residual specimen into 2% glutaraldehyde or sodium hypochlorite –Process positive blood cultures in a BSL-2 cabinet –Referral of specimens- appropriate packaging, inform receiving laboratory Virology: –Routine specimens- as above –VHF diagnosis- requires BSL 3-4 laboratory

BSL-2 cabinet ? provide personnel, environmental and product protection Approx 30% air exhausted, 70% re- circulated A. front opening B. sash C. exhaust HEPA filter D. rear plenum E. supply HEPA filter F. blower

BSL-4 laboratory? dangerous and exotic agents that pose a high individual risk of aerosol-transmitted laboratory infections and life-threatening disease special engineering and design features to prevent microorganisms from being disseminated into the environment. Activities are confined to Class III biological safety cabinets, or Class II biological safety cabinets used with one-piece positive pressure personnel suits ventilated by a life support system.

Laboratory safety: BSL- 4 In contrast to patient-care, high-level protection required for: Laboratory manipulation Mechanical generation of aerosols Concentrated infectious material Viral culture

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