Current Public Health Attitudes:
Toxoplasmic encephalitis is a rare disease in the United States and research has yet to be done on its incidence. In terms of prevalence, 15% of HIV+ Americans are seropositive for a latent Toxoplasma infection. Of this 15%, only 30% are at risk for developing toxoplasmic encephalitis (Remington 2007). Despite its high associated mortality, toxoplasmic encephalitis in HIV+ patients has been unable to attract the attention of U.S. health policy and education campaigns. This is in sharp contrast with countries such as Germany and France, where seroprevalence rates are up to 75% and toxoplasmosis has become a serious health issue adopted by policymakers.
The Centers for Disease Control have established clinical guidelines for the management of toxoplasmosis in immunocompromised patients by U.S. physicians. The CDC guideline mandates the administration of primary, and where necessary, secondary prophylaxis for T. gondii-specific IgG seropositive HIV+ patients. Although adherence to these guidelines is considered the basic standard of care for U.S. doctors, neither this treatment regimen nor the screening of HIV+ patients for IgG antibodies has been addressed with actual health policy.
Waiting for the Window of Opportunity:
According to Dr. Jack Remington, there is a serious lack of political attention to prevention and treatment issues for toxoplasmic encephalitis, and there are no indicators that this situation will improve in the near future. However, greater public health awareness would promote valuable education and research on toxoplasmosis. Widespread education about the causes and treatment options of toxoplasmic encephalitis would be invaluable to HIV+ patients, whether or not they are seropositive. T. gondii-seronegative, HIV-infected persons should be instructed about measures to prevent acquisition of infection, such as avoiding uncooked meat, thoroughly washing fruits and vegetables and avoiding contact with materials that may be contaminated by cat feces (Subauste 2006).
Seropositive patients who are educated about initial symptoms of toxoplasmic encephalitis can seek medical treatment in the early stages of encephalitis and decrease their risk of mortality. Fortunately, because of the serious consequences for AIDS patients, the HIV+ community is well educated. However, because many people do not know they are HIV+, education programs that reach the population outside the HIV+ community are important to managing toxoplasmosis. That said, such public health education campaigns are unlikely to manifest without support from the medical and political community.
The Future of Research:
Political awareness can help generate crucial funding for toxoplasmosis research. Improved diagnostics must be developed to facilitate early detection of infection in HIV+ hosts. According to the CDC, Toxoplasma-specific IgG antibody levels in AIDS patients are often low to moderate, and occasionally no specific IgG antibodies can be detected.
Furthermore, more effective and less toxic treatment regimens must be developed to encourage better adherence to prophylaxis. Current treatment with sulfadiazine and pyrimethamine is often associated with severe side effects such as rashes.
A Toxoplasma vaccine, however, would be the technological advancement that would allow the most efficient prevention and management of T. gondii infection. However, very little progress has been made thus far into vaccine research for use in humans; current research has focused on vaccines that provide immunity in farm animals, including sheep. Without political and financial support, there is little hope for a human vaccine in the near future (Remington 2007).
Health Policy Actions:
In addition to support for education and research campaigns, concrete health policy actions can be taken for improved management of toxoplasmic encephalitis. Mandatory serologic testing for Toxoplasma-specific IgG antibodies in patients diagnosed with HIV should be enforced by law. Such testing is already mandatory in countries such as Germany and France for pregnant women in order to prevent congenital transmission of toxoplasmosis. A doctor aware of a HIV+ patient's seropositivity could immediately conduct an MRI or CT scan upon first clinical signs of encephalitis. This would prevent the fatal progression of the disease.
The promotion of prophylactic treatment to HIV+ positive patients would be an extremely cost-effective strategy for the health care system. A study conducted by the Boston Medical Center on the cost-effectiveness of strategies to prevent AIDS-related opportunistic infections indicated that prophylaxis against toxoplasmosis delivers one of the greatest comparative values among treatment strategies. The study also indicated that both costs of care and mortality rates for progressed toxoplasmic encephalitis are some of the highest among AIDS-related opportunistic infections. There are clear incentives, in the form of lives and dollars saved, to mandatory serologic testing and subsequent prophylactic treatment, where necessary, in HIV+ patients.
Where do we from here?
Analysis of cost-effectiveness of such mandates has not been done for toxoplasmosis in immunocompromised patients. Such research has been done on the cost-effectiveness of screening for congenital toxoplasmosis. If the same research into the social, medical and economic benefits of appropriate management can be done for toxoplasmosis in HIV+ patients, it may generate the policy changes outlined above.
However, the low incidence of disease and subsequent political inattention make such change unlikely in the near future. And, without political will to promote even those existing, effective prevention and treatment strategies, it is even more unlikely that new medical innovation in management of this disease can happen soon.
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