The Medical Research Foundation of Trinidad and Tobago, 7 Queen's Park East, Port of Spain, Trinidad, West Indies.
Received 4 March, 2005
Accepted 4 May, 2005
In a paper published in 1993, Richman and Rickman  had concluded that ‘transmission of HIV through human bites is biologically possible but remains epidemiologically insignificant, and as yet, not well documented’ .
We report a case of a child, who at the age of 3 years was bitten on the middle finger of her left hand by her father in September 2000, causing bleeding at the site. He had multiple sex partners in the past and had a history of dental caries and bleeding gums for years. He was known to have diabetes. He was first discovered to be HIV-antibody positive in June 2004, 3 years after the bite. His CD4 cell count was 4 cells/μl. No viral load assay was done. He died on 17 September 2004.
The child's mother was HIV-antibody negative when tested in June 2004. Sexual intercourse had been infrequent over the past 7 years because he was impotent as a result of his diabetes. Recalling the incident of the bite, the young child was brought by the mother to the clinic of the Medical Research Centre, Port of Spain, Trinidad, for testing. Her HIV antibody assay was positive by enzyme-linked immunosorbent assay and Western blot, her viral load was 20 909 copies/ml and her CD4 cell percentage was 23%. There was no history of sexual abuse or blood transfusion. The cause of the child's infection is believed to be a direct result of the bite from her father.
The first suggestion that the transmission of HIV by a human bite was biologically possible was in a paper by Wahn et al.  from Dusseldorf in 1986, who reported that a young child had died of AIDS at one year of age. There were no risk factors for the child's infection other than a bite on his forearm by his younger HIV-positive brother approximately 6 months before he died. It was suggested that the likely route of virus transmission was the bite from the seropositive younger brother.
In August 1987, there was a brief case report of a 26-year-old healthcare worker with no risk factors for HIV infection, who in early 1985 had a fight with her sister, an HIV-positive intravenous drugs abuser since 1980. During the fight, which caused bleeding in the mouth, she was bitten on the leg by her HIV-positive sister. Stored sera from the bitten sister was found to be HIV-antibody seronegative on 10 August 1983 (before the fight), but she was discovered to be seropositive on 12 January 1987. It was believed that the most likely route of her infection was the bite from her sister .
In 1996, Vidmar et al.  reported the case of a 47-year-old man, who, during late-stage HIV infection with a high HIV-RNA count, had a grand mal seizure in May 1995. A neighbour was bitten when placing his fingers in the man's mouth trying to prevent obstruction of his airway. The bite resulted in a small crack and a shallow wound on the left index fingernail. There was blood in the epileptic patient's saliva from a bite wound on his tongue as a result of the seizure. He died 13 days after the incident. Serum taken from the bitten man on the day of the incident was negative for HIV antibodies, p24 antigen and HIV RNA. However, he seroconverted 54 days after the incident.
Andreo et al.  in 2004 reported a case of an HIV-positive 31-year-old man who bit his mother on her hand during a seizure in November 1999. Blood was present in his mouth at the time of the bite, and the mother needed a suture in her hand. She was a 59-year-old widow who had had no sexual intercourse for the past 10 years. Forty days after the bite, she was found to be HIV positive by enzyme-linked immunosorbent assay and Western blot. A sensitive/less sensitive immunoassay of the blood sample confirmed a recent infection with HIV .
Apart from the brief case report of 1987 , which gave no indication of the stage of infection of the source patient, all the other transmissions of HIV from human bites were from patients in late-stage disease [8,9].
1. Richman KM, Rickman LS. The potential for transmission of human immundeficiency virus through human bites. J Acquir Immun Defic Syndr 1993; 6:402–406.
2. Pretty IA, Anderson GS, Sweet DJ. Human bites and the risk of human immunodeficiency virus transmission. Am J Forensic Med Pathol 1999; 20:232–239.
3. Wahn V, Kramer HH, Voit T, Bruster HT, Scrampical B, Scheid A. Horizontal transmission of HIV infection between two siblings. Lancet 1986; ii:694.
4. Anonymous. Transmission of HIV by human bite. Lancet
5. Vidmar L, Poljak M, Tomazic J, Seme K, Lavs I. Transmission of HIV-1 by human bite. Lancet 1996; 347:1762.
6. Andreo SM, Barra LA, Costa LJ, Sucupira MC, Souza E, Diaz RC. HIV type 1 transmission by human bite retroviruses. AIDS Res Hum Retroviruses 2004; 20:349–350.
7. Janssen RS, Satten GA, Stramer SL, Rawal BD, O'Brien TR, Weiblen BJ, et al
. New testing strategy to detect early HIV-1 infection for use in incidence estimates and clinical and prevention purposes. JAMA 1998; 280:42–48.
8. Fox PC, Atkinson JC, Wolff A, Baum BJ, Yeates C. Salivary inhibition of HIV-1 infectivity: functional properties and distribution in men, women, and children. JADA 1989; 118:709–711.
9. Tereskerz TM, Bentley M, Jagger J. Risk of HIV-1 infection after human bites. Lancet 1996; 348:1512.