Jose A. Serpa

Chagas disease: "the new HIV/AIDS of the Americas".

Endemic Chagas disease has emerged as an important health disparity in the Americas. As a result, we face a situation in both Latin America and the US that bears a resemblance to the early years of the HIV/AIDS pandemic.

Neurocysticercosis: Neglected but Not Forgotten

Neurocysticercosis (NCC) is an infection of the central nervous system caused by the larval form of the tapeworm Taenia solium. Infections occur following the accidental ingestion of tapeworm ova found in human feces. NCC is a major cause of epilepsy and disability in many of the worlds poorer countries where families raise free-roaming pigs that are able to ingest human feces. It is frequently diagnosed in immigrant populations in the United States and Canada, reflecting the high endemicity of the infection in their countries of origin [1]. Although parenchymal cysts are the most common location in the brain and cause seizures, cysts may also be present in the ventricles, meninges, spinal cord, eye, and subarachnoid spaces. Involvement in these other sites may result in aberrant growth (racemose cysts) and complicated disease that is difficult to treat and may cause increased morbidity and mortality.

Acute Bacterial Pneumonia is Associated With the Occurrence of Acute Coronary Syndromes

A link between acute infections and the development of acute coronary syndromes (ACS) has been proposed. We used retrospective cohort and self-controlled case series analyses to define the closeness of the association between acute bacterial pneumonia due to Streptococcus pneumoniae or Haemophilus influenzae and ACS. For the retrospective cohort analysis we included a control group of patients with admission diagnoses other than pneumonia or ACS. For the self-controlled case series analysis, we made within-person comparisons of the risk for ACS during the 15 days after admission for pneumonia with that of 365 days before and after that event. In 206 pneumonia patients (144 S. pneumoniae, 62 H. influenzae) we identified 22 (10.7%) cases of ACS, which compared to 6 (1.5%) among 395 controls resulted in an odds ratio (OR) of 7.8 (95% confidence interval [CI], 3.1-19.4). With multivariate logistic regression analysis, the OR for ACS in the pneumonia group remained elevated (OR, 8.5; 95% CI, 3.4-22.2). By the self-controlled case series method, the risk of ACS remarkably increased during the first 15 days after the diagnosis of pneumonia (incidence rate ratio, 47.6; 95% CI, 24.5-92.5). The characteristics and strength of these associations suggest a causal role for the acute infection in this relationship. Abbreviations: ACS = acute coronary syndromes, CI = confidence interval, ICU = intensive care unit, IRR = incidence rate ratio, OR = odds ratio.

Neurocysticercosis in Houston, Texas: an update.

Neurocysticercosis, one of the most common parasitic infections of the human nervous system, has emerged as an important infection in the United States. Neurocysticercosis causes significant morbidity associated with acute seizures, chronic epilepsy, and hydrocephalus. We retrospectively identified patients with definitive or probable neurocysticercosis seen at Ben Taub General Hospital, the largest public teaching hospital in Houston, Texas, from September 1997 through December 2005. We collected demographic, clinical, therapeutic, and outcome variables. Neurocysticercosis was classified according to the location of cysts in imaging studies. We compared cases with parenchymal and extraparenchymal disease. We included 111 patients (48 had definitive and 63 probable neurocysticercosis). The mean age was 28.6 years (standard deviation, 13.6 yr), and the male to female ratio was 2:1. Most patients (93%) were Hispanic immigrants. Sixty (54%) patients had parenchymal disease, 22 (20%) intraventricular, 13 (12%) subarachnoid disease, and 13 (12%) had calcifications only. Additionally, 2 patients had hydrocephalus only, and 1 had ocular cysticercosis. Thirteen (40%) of 32 patients with parenchymal disease and 3 (30%) of 10 patients with calcifications had relapsed seizures at follow-up. Extraparenchymal disease was associated with longer duration of hospitalization compared with parenchymal disease. No deaths were identified in our series during a median follow-up of 1 year. Neurocysticercosis has emerged as an important parasitic infection in developed countries as a result of increased migration. With current management, mortality is limited, but there continues to be significant morbidity. Further studies of the epidemiology and pathophysiology of the infection are urgently needed to develop better preventive and therapeutic strategies. Abbreviations BTGH = Ben Taub General Hospital, CSF = cerebrospinal fluid, CT = computed tomography, EITB = enzyme-linked immunoelectrotransfer blot, HCHD = Harris County Hospital District, ICD9 = International Classification of Diseases, 9th revision, MRI = magnetic resonance imaging, NCC = neurocysticercosis, US = United States, VPS = ventriculoperitoneal shunt.

The obesity paradox in community-acquired bacterial pneumonia

BACKGROUND The impact of obesity on the outcome of pneumonia is uncertain. METHODS We retrospectively identified 266 hospitalized patients with proven pneumococcal or Haemophilus community-acquired pneumonia who had at least one body mass index (BMI, kg/m²) value documented in the 3 months before admission. Patients were classified as underweight (BMI <18.5), normal weight (BMI 18.5 to <25), overweight (BMI 25 to <30), or obese (BMI ≥30). The association of absolute BMI values and BMI categories with the mortality at 30 days after admission for pneumonia was investigated. RESULTS Increasing BMI values were associated with reduced 30-day mortality, even after adjustment for significant covariates (odds ratio 0.88, confidence interval 0.81-0.96; p<0.01). There was a significant trend towards lower mortality in the overweight and obese (non-parametric trend, p=0.02). CONCLUSIONS Our data suggest that obesity may exert a protective effect against 30-day mortality from community-acquired bacterial pneumonia.

Advances in the diagnosis and management of neurocysticercosis.

Neurocysticercosis is the most common cause of late-onset epilepsy in developing countries. The larval stage of Taenia solium is the causative agent of the disease. Recent advances in neuroimaging and serologic diagnostic techniques have led to increased recognition of its importance, but its pathogenesis is just beginning to be clarified. Experts now agree that the clinical manifestations, pathogenic mechanisms and optimal treatment vary with the number of parasites, their location and the degree of host inflammation. Symptomatic therapy (i.e., antiepileptic medications and, when indicated, surgery) is critically important but there are also important roles for antiparasitic and anti-inflammatory drugs. Neurocysticercosis is a potentially eradicable disease but this is probably unlikely to be achieved in the short term.

The spectrum of invasive pneumococcal disease at an adult tertiary care hospital in the early 21st century.

Despite widespread pneumococcal vaccination of children and adults, invasive pneumococcal disease (IPD) remains prominent. Using our database of all Streptococcus pneumoniae infections at the Veterans Affairs Medical Center, Houston, Texas, since 2000, we reviewed cases of IPD, defined as the isolation of pneumococci from any normally sterile body site. In 136 cases, the mean age of patients was 63 years; 43% were African American, a higher proportion than the 30% served by our hospital. One hundred sixteen patients (85%) had pneumonia, of whom 3 also had empyema. Seven had bacteremia with no apparent source, 5 meningitis, 5 spontaneous bacterial peritonitis, 3 septic arthritis, 2 endocarditis, and individual patients had osteomyelitis and/or localized abscesses. One hundred twenty-one patients (89%) had ≥1 underlying condition associated with susceptibility to pneumococcal infection, and another 8 (6%) were aged >65 years old. Thus only 5% of patients lacked a condition for which 23-valent pneumococcal polysaccharide vaccine (PPV23) is recommended. Fifty-five percent had been vaccinated; similar proportions of vaccine serotypes infected previously vaccinated and nonvaccinated patients. All but 2 isolates were fully susceptible to penicillin and cefotaxime as currently defined. Consistent with substantial replacement of infecting serotypes since the introduction of 7-valent pneumococcal conjugate vaccine (PCV7), none of the predominant infecting serotypes was included in PCV7, although all except for 6A were contained in PPV23. The overall mortality at 30 days was 16% and was similar in vaccinated and nonvaccinated subjects. IPD causes a wide spectrum of disease. Mortality is substantial. PPV23 is clearly not fully protective. Abbreviations: CSF = cerebrospinal fluid, IPD = invasive pneumococcal disease, MEDVAMC = Michael E. DeBakey Veterans Affairs Medical Center, MIC = minimum inhibitory concentration, PCR = polymerase chain reaction, PCV7 = 7-valent pneumococcal conjugate vaccine, PPV23 = 23-valent pneumococcal polysaccharide vaccine. Abbreviations: CSF = cerebrospinal fluid, IPD = invasive pneumococcal disease, MEDVAMC = Michael E. DeBakey Veterans Affairs Medical Center, MIC = minimum inhibitory concentration, PCR = polymerase chain reaction, PCV7 = 7-valent pneumococcal conjugate vaccine, PPV23 = 23-valent pneumococcal polysaccharide vaccine.

Tuberculosis disparity between US-born blacks and whites, Houston, Texas, USA

An unusually high proportion of cases in Houston are caused by active transmission of endemic strains among US-born non-Hispanic blacks.

Substance P causes seizures in neurocysticercosis.

Neurocysticercosis (NCC), a helminth infection of the brain, is a major cause of seizures. The mediators responsible for seizures in NCC are unknown, and their management remains controversial. Substance P (SP) is a neuropeptide produced by neurons, endothelial cells and immunocytes. The current studies examined the hypothesis that SP mediates seizures in NCC. We demonstrated by immunostaining that 5 of 5 brain biopsies from NCC patients contained substance P (SP)-positive (+) cells adjacent to but not distant from degenerating worms; no SP+ cells were detected in uninfected brains. In a rodent model of NCC, seizures were induced after intrahippocampal injection of SP alone or after injection of extracts of cysticercosis granuloma obtained from infected wild type (WT), but not from infected SP precursor-deficient mice. Seizure activity correlated with SP levels within WT granuloma extracts and was prevented by intrahippocampal pre-injection of SP receptor antagonist. Furthermore, extracts of granulomas from WT mice caused seizures when injected into the hippocampus of WT mice, but not when injected into SP receptor (NK1R) deficient mice. These findings indicate that SP causes seizures in NCC, and, suggests that seizures in NCC in humans may be prevented and/or treated with SP-receptor antagonists.

Quantitative and Qualitative Antibody Responses to Immunization With the Pneumococcal Polysaccharide Vaccine in HIV-Infected Patients After Initiation of Antiretroviral Treatment: Results From a Randomized Clinical Trial

BACKGROUND Pneumococcal vaccination is recommended for human immunodeficiency virus-infected (HIV+) persons; the best timing for immunization with respect to initiation of antiretroviral therapy (ART) is unknown. METHODS Double-blind, placebo-controlled trial in HIV+ with CD4(+) T cells/µL (CD4) ≥ 200 randomized to receive the 23-valent pneumococcal polysaccharide vaccine (PPV23) or placebo at enrollment, followed by placebo or PPV23, respectively, 9-12 months later (after ≥6 months of ART). Capsular polysaccharide-specific immunoglobin (Ig) G and IgM levels to serotypes 1, 3, 4, 6B, and 23F, and opsonophagocytic killing activity (OPA) to serotypes 6B and 23F were evaluated 1 month postvaccination. RESULTS One hundred seven subjects were enrolled, 72 (67.3%) were evaluable (36/group). Both groups had significant increases in pre- to 1-month postvaccination IgG levels, but negligible to IgM, and significant increases in OPA titers to serotype 6B but not to 23F. There were no significant differences between groups in serotype-specific IgM or IgG levels or OPA titers. For the combined groups, there was a significant correlation between serotype-specific IgG and OPA titers to 23F but not to 6B. There was no correlation between CD4, viral load and IgG responses. CONCLUSIONS In HIV+ with CD4 ≥ 200, delaying PPV23 until ≥6 months of ART does not improve responses and may lead to missed opportunities for immunization.