Updates

By Carol A. Kemper, MD, FACP, Clinical Associate Professor of Medicine, Stanford University, Division of Infectious Diseases; Santa Clara Valley Medical Center, Section Editor, Updates; Section Editor, HIV, is Associate Editor for Infectious Disease Alert.

HIV Epidemic in India: Personal Experience From Silicon Valley

Source: R. Steinbrook. HIV in India — A complex epidemic. N Engl J Med. 2007;356 (11):1089-1093.

The San Francisco Bay area is now home to one of the largest Asian Indian populations in the United States, especially in Silicon Valley, where it is estimated that 40% of the computer programmers are Asian Indian. As a result, I see more endemic disease (eg, typhoid, salmonella sepsis, malaria and tuberculosis) in a community-based private practice than I ever did at the county hospital. There has been, however, one unique addition to my practice over the past 2 years: 6 Asian Indian patients with HIV, who represent ~5% of my total HIV/AIDS practice. Two are female and 4 are male. One young woman, aged 24 years, has a hidden history of abuse. The other woman is in her early 40s and was a practicing surgeon in India before moving to the United States, where she is a housewife. She presented with a CD4 count of 90 cells/mm3 but was virtually asymptomatic. The 4 men are bisexual or have had sex with men, though were reluctant to disclose this information. Homosexuality is illegal in India and punishable by the same Penal Code as sex offenders, pedophiles, and people who have sex with animals.

With the exception of the housewife, all work in high tech and were unaware of their HIV status. Infections in all 5 were detected when HIV tested for immigration purposes. While it is possible that the men may have acquired their HIV in the United States, the timing and CD4 cell count results suggest earlier infection.

It is interesting that this experience parallels the emerging epidemic in India, as outlined by Dr. Steinbrook. It is estimated that somewhere between 3.4 and 9.4 million persons in India are infected with HIV, although less than 10% are aware of their status. The estimated prevalence of infection among persons aged 15 to 49 years old is 0.5 to 1.5%. However, prevalence data for much of India is lacking. Of India's 35 states, 6 are considered high prevalence based on observations of HIV seropositive rates > 1% in woman getting prenatal testing and rates > 5% at STD clinics. But many states don't offer prenatal screening, and treatment during pregnancy or peripartum is limited.

HIV prevalence studies in Indian sex workers typically find rates of 10% to 20%, with an estimated number of 2 million female sex workers and 235,000 male sex workers. In addition, India has an estimated 2.35 million men who have sex with men — although many would not identify themselves as such. According to Dr. Steinbrook, sex between men is often considered "mischief."

An important part of the emerging epidemic is the 5 million truckers in India. Similar to the experience in Africa, sex work along the main truck routes is common, bringing the epidemic home to housewives in rural areas. In Chennai (formerly Madras) in southern India, one fourth of HIV+ clients at one treatment center were housewives. Spousal violence against women astoundingly ranges from 16% to 44% , depending on the city. It is no wonder that the Joint United Nations HIV Program in India found "it is not possible to control the overall HIV epidemic if it is out of control in India."

Physicians in the United States should be aware that Asian Indians without readily identifiable risk factors may have HIV. Public health experts advocate stepping up HIV screening in all persons with tuberculosis. Just because someone from India is at increased risk for reactivation TB doesn't mean they don't have HIV. Similar logic should apply to any Asian Indian with salmonella bacteremia, pneumonia, or hospitalization for infection.

HIV+ Patients Still Need PCP Prophylaxis

Source: Teshale EH, et al. Reasons for lack of appropriate receipt of primary Pneumocystis jiroveci pneumonia prophylaxis among HIV-infected persons receiving treatment in the United States: 1994-2003, Clin Infec Dis. 2007; 44:879-883.

Prophylaxis against PCP remains the single most cost-effective intervention in HIV+ patients at risk. But treatment has, in some ways, become a moving target in some patients, as their CD4 count rises and falls with newer HIV therapies, medication side effects, and variable compliance. Despite the increased use of highly active antiretroviral therapy, this Atlanta-based clinic reported an unusually high number of PCP cases. During a 4-year period from 1999-2003, 483 cases of PCP were diagnosed during 7315 person years. The incidence in persons receiving both HAART and PCP prophylaxis was low (5.2 episodes per 100 person years). However, the rates of PCP in persons who had an initially favorable CD4 response but later dropped their CD4 below 200 cells/mm3, those that stopped prophylaxis while their CD4 count was < 200 cells/mm3, or those that never started below 200 cells/mm3 were 6.3, 11.3 and 19.2 episodes per person per year, respectively. Rates for persons with CD4 < 100 were greater.

Women, Latinos, injection drug users, those new to treatment, and those with fewer clinic visits were significantly less likely to receive PCP prophylaxis. Physicians need to be aware of the potential "gap" in PCP prophylaxis for these at-risk subjects. Additional research is needed to determine if there is benefit in maintaining or starting at-risk subjects on PCP prophylaxis at higher CD4 counts, eg, 250 cells/mm3, recognizing the benefits may outweigh the risks. In addition to decreasing the risk of PCP, prophylaxis with trimethoprim-sulfame-thoxazole has been found to decrease the risk of bronchitis and sinus infection, and recent data found that HIV+ patients maintained on trimethoprim-sulfamethoxazole were at lower risk for infection with MRSA.

Increase in Neurocysticercosis in the United States

Source: Sorvillo FJ, et al. Deaths from Cysticercosis, United States. Emerging Infect Dis. February 2007; 13(2): www.cdc.gov/eid.

An increasing number of cases of neurocysticercosis are occurring in the Western United States bordering Mexico, and in cities with large immigrant populations, such as New York and Philadelphia. Vouching from personal experience working in a large county hospital in Santa Clara County, California, our state gets more than its fair share of cases. California reported 44 cases of neurocysticercosis in 2005 and 45 cases during the first 10 months of 2006. And those are just the reported cases. Nearly 60% of all U.S. deaths from cysticercosis between 1999-2002 occurred in California residents. The mean age at death was 40.5 years. Only 33 (15%) were U.S.-born, and the rest were foreign born, two-thirds from Mexico. Similarly, the Los Angeles County Public Health Department reported that ~12% of county-based cysticercosis cases had no history of travel and had no significant risk factors for infection.

When doing ward rounds, 3 misconceptions are commonly voiced:

(1) Lack of a recent travel history excludes the diagnosis;

(2) Persons born in the U.S. without a travel history are not at risk for cysticercosis;

(3) Cysticercosis comes from eating "bad pork."

Eating infected pork meat for example, in Mexico, results in the intestinal tapeworm phase of infection with Taenia solium. These persons excrete tapeworm eggs in the stool. Should these individuals migrate across the U.S. border, they can be a source of infection for U.S. residents. Individuals may be exposed by eating fruits or vegetables contaminated in the field (by feces in the soil or by unwashed hands) or from food handlers, restaurant workers, personal cooks or visitors with inadequately washed hands. These ingested eggs pass through the system, migrate through muscle or organs (eg, brain or spinal cord), where they encyst, hoping to be eaten some day, so they can grow up to be a tapeworm. It may take 2-3 years for a person with neurocysticercosis to present with symptoms, typically as the cyst begins degenerating, causing a vigorous immunological response with brain edema and seizures. At that point, treatment of dead or dying cysts may not be helpful. Some patients may simply present years later with seizures from focal scarring from dead cysts. Patients may be left with residual neurologic impairment or chronic seizures. In Hispanics, it is reported that neurocysticercosis results in 13% of all emergency room visits for seizures.

Physicians should keep in mind that, while cystercosis remains an increasingly common problem for Latino immigrants, U.S. born persons without identifiable risk factors may also be affected.

Can Influenza Protect You Against Avian Flu?

Source: Sandbulte MR, et al. Cross-reactive neuraminidase antibodies afford partial protection against H5N1 in mice and are present in unexposed humans? PLoS Med. 2007Feb 13;4(2):e59.

Hoping to find evidence of cross-protection from infection or immunization with Influenza A and avian flu, these authors immunized a series of mice with DNA vaccine containing human H1N1 viruses. In addition, naïve mice were passively immunized using sera from vaccinated mice. Immunization resulted in a vigorous IgG antibody response with good protection against human Influenza A virus (A/Puerto Rico/8/ 34 with huN1) on challenge.

Partial cross-reactivity was observed when immunized mice were challenged with a lethal dose of either H5N1 virus (A/Vietnam/ 1203/ 2004) or a recombinant avian N1 strain. Passive antibody protection was also protective when non-immunized naïve mice were given a lethal challenge of avian viruses. These data suggest that individuals vaccinated with H1N1 virus, or previously infected with circulating H1N1 virus may have partial cross-protection against avian influenza virus. Seasonal N1-containing Influenza virus circulating within the community may result in anywhere from 10% to 40% of cases, resulting in more durable immunity than that resulting from vaccination. Thus, whether individuals may have partial protection against avian flu without knowing it remains to be determined but seems possible.