Herpes B virus Flashcards
What animal is the reservoir of this infection?
Macaque monkey
How is it transmitted?
bite/ scratch from macaque or where fluids from monkey got on to broken skin, such as a cut
one lab member died after being splashed in eye by faeces
What is incubation period?
3-7 days
can be up to 1 month
What are clinical symptoms of infection?
Flu-like illness
vesicular lesions can occur at exposure site
lymphadenitis
spread to CNS:
hyperasthesia
ataxia
diplopia
agitation
ascending flaccid paralysis
if CNS symptom develop - most will die
death usually from respiratory failure due to ascending paralysis
How to diagnose Herpes B virus
How do we assess the risk of Herpes B infection?
Type and physical condition of the implicated animal. Only monkeys of the macaque family serve as the natural reservoir for B virus infection. No other primates carry any risk of B virus transmission unless they have become infected by a macaque. Infected macaques do not ordinarily shed B virus. Animals with wounds consistent with B virus infection (fluid-filled blisters on the skin) and animals that are immunocompromised or stressed are far likelier to be excreting virus.
Thoroughness and timeliness of wound cleansing procedure. Wounds that have been cleansed within five minutes of exposure and that have been irrigated for at least 15 full minutes are less likely to lead to B virus infection. Delay in cleansing or inadequate irrigating of the wound increases the risk of infection.
Nature of the wound. Bites or scratches that break the skin, and particularly deep puncture wounds, are considered higher risk than wounds that are superficial and thus more easily cleansed. Wounds to the head, neck, or torso provide potentially rapid access to the central nervous system (CNS) and thus should be considered higher risk. Prophylaxis is recommended for this type of wound, regardless of its severity. Superficial wounds to the extremities are less likely to lead to fatal disease, and antiviral treatment is considered less urgent in these cases.
Exposure to materials that have come into contact with macaques. Accidental needle sticks with syringes that have come into contact with the CNS, eyelids, or mucosa of macaques are considered to carry a high risk of infection. Punctures from needles exposed to the blood of macaques are considered relatively low risk. Scratches resulting from contact with possibly contaminated objects, such as animal cages, are considered to carry a low risk for infection
Risk is never zero even with perfect history. So need to decide whether to treat or not
Who should be treated, following macaque exposure?
Definite Treatment is recommended
Skin or mucosal exposure – with or without injury – to a high-risk source (e.g., a macaque that is ill, immunocompromised, known to be shedding virus, or has lesions compatible with B virus infection.)
Inadequately cleansed skin exposure (where the skin is broken) or mucosal exposure (with or without injury).
Laceration of the head, neck, or torso.
Deep puncture bite.
Needle stick associated with tissue or fluid from the nervous system, lesions suspicious for B virus, eyelids, or mucosa.
Puncture or laceration with objects (a) contaminated either with fluid from monkey oral or genital lesions or with nervous system tissues or (b) known to contain B virus.
A culture taken after the wound was cleansed tests positive for B virus.
When would treatment not be recommended?
Skin exposure in which skin remains intact
exposure to non-macaque species of monkeys
What is prophylactic treatment for herpes B infection?
Prohylaxis following exposure
- aciclovir 800mg x5 doses for 14 days
What is treatment for herpes B infection?
With and without CNS symptoms
Wound cleaning
Without CNS symptoms
aciclovir 12.5-15mg/kg TDS
With CNS symptoms
Ganciclovir 5mg/kg BD
After treatment, there is a risk of reactivation in future.
So following 14 days treatment, needs 6-12 months post-exposure aciclovir, and may need lifelong suppressive therapy
CDC guidelines
Following treatment for Herpes B infection, which patients require long-term aciclovir treatment?
14 days initial treatment
6-12 months aciclovir 800mg 5x
Lifelong suppressive therapy - no data for this
After treatment, there is a risk of reactivation in future.
So following 14 days treatment, needs 6 months post-exposure aciclovir, and may need lifelong suppressive therapy
CDC guidelines
