Possible transmission of HIV Infection due to human bite
© Deshpande et al; licensee BioMed Central Ltd. 2011
Received: 23 December 2010
Accepted: 31 March 2011
Published: 31 March 2011
The potential risk of HIV-1 infection following human bite although epidemiologically insignificant, but it is biologically possible. There are anecdotal reports of HIV transmission by human bites particularly if saliva is mixed with blood. The oral tissues support HIV replication and may serve as a previously unrecognized HIV reservoir. The HIV infected individuals have more viruses in blood than saliva, possibly due to the potent HIV-inhibitory properties of saliva. The case presented here is of a primary HIV infections following a human bite where in the saliva was not blood stained but it got smeared on a raw nail bed of a recipient. The blood and saliva of the source and blood of the recipient showed a detectable viral load with 91% sequence homology of C2-V3 region of HIV gp120 between the two individuals. The recipient did not receive PEP [post exposure prophylaxis] as his family physician was unaware of salivary transmission. The family physician should have taken PEP decision after proper evaluation of the severe and bleeding bite. Hence it is necessary to treat the HIV infected human bites with post exposure prophylaxis.
The epidemiological data has supported the premise that HIV transmission via saliva is low or non-existent due to inhibitory factors in saliva. The risk of HIV-1 infection following human bite although epidemiologically insignificant, but it is biologically possible [1, 2]. Animal studies with rhesus macaques shows the infants are more susceptible to oral infections . The oral trauma, co-infections with other sexually transmitted pathogens, periodontal diseases, concomitant ulcerative lesions, further enhance oral HIV transmission. The human bites as a rare risk factor for HIV transmission . Some patients are hyper-excretors  they have high levels of infectious HIV in their saliva than in blood. These hyper-excretors may be at risk of transmitting the virus to their partners even though the blood viral load is low.
An interesting case of HIV transmission following a human bite is reported.
On 29 March 2010, a 44 year's old man (Mr.A) a known case of NIDDM (Non-insulin dependent diabetes mellitus) and hypertension for past four years under treatment was brought to the hospital with history of high grade fever and increasing drowsiness for past four days.
Clinical examination revealed a drowsy febrile patient without focal neurological deficit or meningeal signs. A clinical diagnosis of malaria, metabolic encephalopathy with sepsis was made, later the patient had two episodes of generalized tonic-clonic convulsions and was treated with midazolam and Loarazepam followed by phosphenytoin along with IV Artesunate. Basic investigations were normal. Malarial parasites were not detected. Computerized tomography (CT) Brain showed nonspecific changes. CSF was suggestive of viral meningitis. Despite inj. Acyclovir drowsiness continued. He was negative for HBV, HCV, and HSV. The HIV Duo test was weakly positive. (Mr. A) did not provide any history of unprotected sex or multiple sex partners, nor any intravenous drug use in past or present, His spouse is HIV negative, The HIV-I viral load on the 4th day of hospitalization was >750,000 copies/ml (Cobas Taqman 48 Real time PCR) and The CD4+ cell count was 396 cells/mm3. A diagnosis of acute HIV infection was considered and TDF+FTC+EFV were started as per DHHS guidelines.
Clinical examination of (Mr.X) revealed that his oral hygiene was good, absence of oral ulcers, caries no bleeding in gums. There were no physical injury, cuts or scratches occurred during the argument. The patient consulted his family physician who did not advice PEP, as salivary transmission of HIV is rare and negligible.
Translated Amino acid sequences of C2-V3 Region of HIV 1C env gene from Peripheral blood mononuclear cells (PBMCs)
NTF NG T
ETS N K T
II-SK NLT DN
TE TIIVQ LD E
IIR SE NLT DN
AK TIIVH LN E
Virological and Immunological parameters
CD4 count Cells/μl
Viral Load Copies/ml
Evidence from the reports of Healthcare workers (HCWs) bitten by HIV infected toddlers highlights universal precautions should be taken . The potential transmission of HIV 1 by human bite retroviruses has also been reported  Detection of HIV-1 in saliva has implications for case identification, clinical monitoring and surveillance for drug resistance  which also reveals detectable salivary HIV RNA may be a useful analyte for detection of HIV infection for monitoring responses to ARV therapy.
Our observations revealed transmission of HIV infection from the smear of non-contaminated saliva of [Mr.X] on the raw and bleeding nail bed of (Mr.A) To conclude, the family physician should have taken PEP decision after proper evaluation of the severe and bleeding bite. Hence it is necessary to treat the HIV infected human bites with post exposure prophylaxis.
Written informed consent was obtained from the patient for publication of this case report and accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal.
All staffs of Department of Biochemistry and Virology National Institute for Research in Reproductive Health (NIRRH) ICMR and ART Centre Sir J J Group of Govt Hospitals Mumbai, India. We are grateful to Indian Council of Medical Research, Government of India for the Senior Research Fellowship to Shivaji K Jadhav.
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