Rare and imported pathogens Flashcards
What is the family and genus of hendra virus?
Henipavirus genus in Paramyxoviridae
What is the reservoir host of hendra virus?
What is the risk factor for human infection?
Where does hendra circulate?
Flying foxes (Pteropus fruit bats)
Close contact with infected horses (not bats)
Only in Australia
What is the main clinical presentation of hendra?
Neurological disease - can be biphasic, encephalitis can occur up to 1 year after acute infection
Is there a vaccine available for hendra?
What treatment has been used?
No human vaccine, only vaccine for horses
Ribavirin has been used for treatment and PEP
mAbs are in development for PEP
What is the family and genus of nipah virus?
Henipavirus genus in Paramyxoviridae
What is the reservoir host of nipah virus?
What is the risk factor for human infection?
Where does nipah circulate?
Flying foxes (Pteropus fruit bats)
Close contact with infected pigs, undercooked horse meat, drinking raw date palm sap
South East Asia (Philippines, Malaysia, Bangladesh, India)
Why is nipah an HCID and hendra not?
No evidence of human to human transmission of hendra
What are the transmission routes of nipah?
Likely respiratory spread
Direct contact with infected secretions and excretions of pigs, bats, humans ?horses
Possible sexual transmission
What are the clinical symptoms of nipah?
What is the fatality rate?
Can be asymptomatic or mild
Sudden onset ILI followed by encephalitis (also meningitis and pneumonia)
Late onset encephalitis (up to 11 years!)
Severe sequalae in survivors
40-70% mortality
What treatment has been used for nipah?
… Ribavirin! (little evidence)
What is the family and genus of EEEV/WEEV/VEEV?
Togaviridae family, alphavirus genus
What does EEEV cause in horses?
Febrile disease leading to encephalitis!
How are humans infected with E/W/VEEV?
When bitten by ‘bridging mosquitos’ which are infected from birds
Mostly Aedes sp.
Which is most severe - EEEV, WEEV, VEEV?
EEEV
What are the reservoir hosts for:
EEEV?
WEEV?
VEEV?
Passerine birds
Passerine birds
Rodents
What is the most severe mosquito borne encephalitides?
EEEV
Where are the following found it the world:
EEEV?
WEEV?
VEEV?
EEEV = Eastern and North USA and Eastern Canada
WEEV = Western USA and Canada, and some of South America
VEEV = South America (both epidemic and enzootic viruses)
Are horses amplifying hosts in EEV/WEEV or VEEV?
VEEV only
Small mammals and rodents are amplifying hosts in EEEV and hares in WEEV
Treatment for EEEV/WEEV/VEEV?
Supportive only
How is the UK blood supply protected from EEEV?
Default deferral of American returners for 28 d due to risk of WNV
What are the mosquito vectors for:
EEEV?
WEEV?
VEEV?
EEEV = Culiseta melanura
WEEV = Culex tarsalis
VEEV = Aedes taeniorhynchus and Culex
Fatality rate of:
EEEV
WEEV
VEEV
EEEV - 30%
WEEV 3-4%
VEEV <1%
What is Sindbis virus?
A virus in the WEEV complex
Causes rash, fever and arthritis
In Eastern hemisphere - mainly Northern Europe
What are Everglades, Mucambo, Tonate and Cabassou viruses?
Viruses of the Venezualean equine encephalitis virus complex
(Alphaviruses)
In which patients is WEEV and VEEV most severe?
Children
What disease do the equine encephalitis viruses cause?
Acute ILI followed by neurological disease
EEEV is biphasic with neurological signs 1-2 weeks after infection, often severe encephalitis
What is the family and genus of chikungunya virus?
Togaviridae family, alphavirus genus
Vector of chikungunya
Aedes aegypti (A. albopictus has been associated with infection in Italy)
Is chikungunya present in Europe?
No, however sustained outbreaks in France and Italy have occurred due to imported travel case
In which countries are UK travellers most at risk of chikungunya?
India, SE Asia, Caribbean
What are the reservoir hosts of chikungunya?
Monkeys and humans
What are the risks of chikungunya in pregnancy?
No congenital infection but CHIKV infection perinatally can cause neonatal meningoencephalitis
Is there a vaccine available for chikungunya in UK?
No, however there is a live attenuated vaccine available in the US
Clinical symptoms of chikungunya
Mild or asymptomatic
Sudden onset fever and joint pain - joint pain is debilitating and arthritis can persist for several months or years
Death is rare
Other than joint pain and ILI what are additional symptoms of chikungunya?
75% of patients have dermatological compications including:
Pigmented rash
Ulcers in groin or oral mucosa
Haemorrhagic lesions
Desquamation
Joint pain and arthritis can last for several months or years
Severe eye, neurological and heart complaints have also been reported
How is the UK blood supply protected from CHIKV?
Blood donors are deferred for 28 d post travel to an at risk country
If infected with CHIKV they are deferred for donation for 6 months
Has there been person to person transmission of CHIKV?
No, and no known cases of blood/organ transmission
What is the family and genus of hantaviruses?
Hantaviridae family, orthohantavirus genus
How many hantaviruses are there - which are the important ones in humans?
Over 40!
New World hantaviruses - Andes and Sin Nombre
Old World hantaviruses - Souel, Hantaan, Puumala and Dobrava
What animals are reservoir hosts for all hantaviruses?
Rodents, each hantavirus species is specific to a different host
What syndromes do Old World vs New World hantaviruses cause?
Old World hantaviruses - Haemorrhagic fever with renal syndrome (HFRS)
New World hantaviruses - Hantavirus pulmonary syndrome (HPS)
Sometimes viruses that cause HFRS can cause HPS and vice versa
How is hantavirus transmitted to humans?
What increases the risk of infection?
Infection via inhalation of infected urine, faeces and saliva
Increased human cases linked to land use changes or excess rainfall allowing rodents to breed more, or to occupational or hobby exposure
What groups are at risk of hantavirus in the UK?
1) Pet rat owners
2) Occupational exposure (farmers, sewage workers, pest control, pet shop workers)
What are the four Old World hantaviruses?
What are their hosts and distribution?
Which is most severe to least severe?
Seoul - SE Asia and worldwide - Rats
Puumala - Western Europe and Scandinavia - Bank Vole (disease called nephropathia epidemica)
Dobrava - Balkans - Yellow necked field mouse
Hantaan - Asia - Field mouse
Hantaan and Dobrava are most severe (15% mortality)
Seoul causes moderate disease
Puumala is mildest (<0.1% mortality)
What is the incubation of hantaviruses?
Usually 2-4 weeks but can range from 2d to 8 weeks
What are the two New World hantaviruses?
What are their hosts and distribution?
Which is most severe?
Sin Nombre - North America - Deer mouse
Andes - South America - Long-tail pygmy rice rat
Both highly pathogenic with 35% fatality rate
Person to person transmission has been documented in which of the hantaviruses? What implication does this have?
Andes hantaviruses - this is classified as an airborne HCID
Are vaccines available for hantaviruses?
Not in UK
Hantaan/Seoul virus vaccine available in China and South Korea (Hantavax)
DNA vaccines expressing proteins from the different hantavirus are in development
What treatment is there for hantaviruses?
Supportive only
Ribavirin and antiserum has been used. UK guidelines specifically say not to use ribavirin or corticosteroids in Andes hantavirus infection
What samples would you test for hantavirus?
RNA testing in blood and urine at RIPL
When would you consider Andes virus infection?
Patients with a relevant travel history (particularly Argentina/Chile in the summer months)
Relevant exposure history - i.e. trekking, hiking
Severe acute respiratory illness within 8 weeks of exposure
Clinical symptoms of hantavirus HFRS
Abrupt onset ILI
Fever
Headache
GI symptoms
Renal dysfunction
Thrombocytopaenia
Haemorrhagic manifestations in severe disease
What are the five stages of HFRS?
- Febrile
- Hypotensive
- Oliguric
- Diuretic
- Convalescent
Clinical symptoms of hantavirus pulmonary syndrome?
Abrupt onset non-specific prodrome
Cough
Tachypnoea
Thrombocytopaenia
Pulmonary oedema
Hypoxia
Capillary leakage in lungs, after onset of cardiopulmonary phase patients deteriorate rapidly
What is the family and genus of SFTSV?
Phenuiviridae family, Bandavirus genus
What other names are used for SFTSV?
Huaiyangshan banyangvirus or Dabie bandavirus
What is the vector of SFTSV?
Haemaphysalis longicornis (Asian long horned tick)
What are the intermediate hosts of SFTSV?
Sheep and goats
Have human to human transmissions occurred in SFTSV?
What are the implications of this?
Yes
SFTSV is classified as a contact HCID
What regions are most at risk of SFTSV?
Mostly rural areas where increased tick numbers are observed
China
Japan
Taiwan
South Korea
Possibly Pakistan and Vietnam
What is the fatality rate of SFTSV?
5%
What genus is La Crosse virus?
Orthobunyavirus
Where does La Crosse virus circulate? What is the vector?
Rural mid-Atlantic and Mid-West USA
Aedes triseriatus (Eastern treehole mosquito)
What are symptoms of La Crosse virus and when does it usually occur?
Mostly asymptomatic
Can cause meningoencephalitis, seizures, cerebral odema and respiratory compromise
Causes ‘paediatric encephalitis’ cases in the summer
What is the family and genus of orapouche?
Peribunyaviridae family, orthobunyavirus
Where does oropouche circulate? What are the reservoir hosts and what is the main vector?
South America
Pale throated sloths, primates and birds
Culicoides paraensis (midge)
Where did the 2024 oropouche outbreak occur?
Mainly Brazil, also to Bolivia, Cuba, Columbia and Peru
Travel linked cases in Spain and Italy
What are the symptoms of oropouche?
What is the risk in immunocompromised?
What is the risk in pregnancy?
Acute febrile illness, severe illness includes meningitis, rash, petechiae, GBS
Death has occurred in patients with underlying conditions
Vertical transmission has occurred and caused foetal deaths
What is the family and genus of Toscana virus?
Phenuviridae family, Phlebovirus genus
What is the main vector of Toscana virus?
Phlebotomus sand fly
Where does Toscana circulate?
Southern Europe, Northern Africa
One of the most frequent causes of aseptic meningitis in SW Europe in summer
What are the symptoms of Toscana virus?
Sudden onset fever, rash nausea, vomiting, myalgia
Neck stiffness in 90%, encephalitis in 40%
Rarely causes death
What is the family and genus of Chandipura?
Rhabdovirus family, vesiculovirus genus
Where and when does Chandipura circulate?
Endemic in India
Occurs sporadically, esp during monsoon season
What is the main vector of Chandipura virus?
Phlebotomus papatasi (sand fly) - also spread by ticks and mosquitos
What are the symptoms of Chandipura?
High grade fever, vomiting, headache
Altered sensorium, convulsions, acute encephalitis/encephalopathy
Death within 48 h
What population is Chandipura most severe in?
What is the fatality rate?
Children under 15 y
50-75% mortality rate
What is the family and genus of Ross River virus?
Togaviridae family, alphavirus genus
Where does Ross River virus circulate?
Australia, Papua New Guinea, South Pacific Islands
What are the symptoms of Ross River virus?
Outbreaks of polyarthritis and arthralgia, also causes rash
(similar to chikungunya)
What is the vector of Ross River virus?
Aedes mosquitos
What is the family and genus of LCMV?
Arenavirus family, mammaarenavirus genus
What is the reservoir of LCMV? Where is it present in the world?
House mouse (sheds virus in saliva, urine, faeces)
Worldwide distribution
What are symptoms of LCMV?
Non-specific symptoms and then CNS disease 2-3 weeks later
Aseptic meningitis or meningoencephalitis
What are the risks of LCMV in pregnancy?
Congenital CNS infection
Ocular lesions
Abortion
Neonatal meningitis
Most congenitally infected neonates have severe neurological deficits, 35% die
How would LCMV present as a transplant transmitted infection?
What treatment would be available?
Severe disease, mostly fatal
Reduction of immunosuppression, and ribavirin
What is herpes B virus?
Alphaherpesvirus
Also known as macacine alphaherpesvirus 1 or herpesvirus simiae
What are the reservoir hosts of herpes B?
Old world macaques
What is the incubation of herpes B virus?
Up to 1 month
What are the symptoms of herpes B?
Non-specific prodrome
Vesicular lesions at exposure site
Hiccups
CNS disease, AFP, death
What would be given for a) PEP and b) treatment for herpes B?
PEP = wound cleaning for 15 mins with soap and water and then rinsed with water for another 15 mins.
Give 800 mg aciclovir 5x day 14 days, and take a blood sample for storage
Treatment = IV aciclovir 15 mg/kg TDS or 5 mg/kg ganciclovir BD if CNS symptoms
