ECTOPARASITES

Causative organism

• Pubic lice is caused by Pthirus pubis

• Scabies is caused by Sarcoptes scabiei var hominis

• See STI Guidelines

Incubation period

• P. pubis– 7-10 days

• Scabies –2-6 weeks; or 1-4 days after re-infestation

How far to trace back

• P. pubis– 7-10 days before onset of symptoms

• Scabies –6 weeks

Usual testing method

• P.pubis– Visual inspection 

• Scabies –Visual inspection +/- skin scrapings

Common symptoms

• P. pubis – itching in the genital area

• Scabies –intense itching particularly at night or after a hot shower/bath

Likelihood of transmission per act of condomless intercourse

•  Unknown but possible

Likelihood of long-term sexual partner being infected

•   Probable

Protective effect of condoms

•  Unknown but unlikely

Transmission by oral sex

• P. pubis–lice can infest facial hair including eyelashes

• Scabies – n/a

Duration of potential infectivity

Until treatment completed. Concurrent laundering of personal clothing and bed linen required.

Important sequelae

• Secondary infection of lesions caused by scratching;

• Lymphadenitis

Direct benefit of detection and treatment of contacts

 Cure

Usual management of contacts

• P. pubis–treatment with effective chemical & advised to launder personal underwear and bed linen used in the previous 7 days prior to treatment

• Scabies –Isolate until after treatment. Advised to launder bed linen and personal clothing used in the 48 hours prior to treatment

Note:

For outbreaks in closed communities, such as residential aged care facilities, all residents and staff who have had contact with residents with scabies require treatment. Quarantine the affected area if possible. If staff from the affected area have worked elsewhere, that area should also be assessed. The source of a scabies outbreak in a residential aged care facility should be identified because the patient may have crusted scabies.

If a school-aged child has scabies, notify the school. Treatment of children who do not have scabies is not required but is highly recommended. Children with scabies can return to school when two treatments for scabies, 1 week apart, are completed.

Contact tracing priority

 Sexual partners and close household contacts

Notification

 Not required