Molecular bloodmeal analyses reveal that Trypanosoma cruzi-infected, native triatomine bugs often feed on humans in houses in central Brazil.

The identification of bloodmeal sources in triatomine bugs (Hemiptera: Reduviidae) is important in understanding vector-host associations and in measuring the risk for Chagas' disease transmission. The bloodmeal sources of triatomines infected with Trypanosoma cruzi (Trypanosomatida: Trypanosomatidae) caught in houses in central Brazil (Goiás State and the Federal District) were investigated during 2012-2014. Mitochondrial cytochrome b amplicons were used to identify bloodmeals through high-resolution melting and DNA sequencing. Most bugs were found to have fed on either humans (45.7%) or chickens (43.1%). Human blood was detected in Triatoma sordida (n = 22/50 bugs), Triatoma pseudomaculata (n = 7/11 bugs), Panstrongylus megistus (n = 10/24 bugs), Panstrongylus geniculatus (n = 1/3 bugs) and Rhodnius neglectus (n = 18/28 bugs) (all: Hemiptera: Reduviidae). Sequencing identified Necromys (Rodentia: Cricetidae) mouse blood in P. geniculatus and Tropidurus (Squamata: Tropiduridae) lizard blood in T. pseudomaculata and T. sordida. These findings reveal new vector-host associations. The present results suggest frequent contact between humans and T. cruzi-infected triatomines in central Brazil and indicate that Chagas' disease transmission by native vectors is an ongoing threat.

Chagas disease.

Chagas disease is the clinical condition triggered by infection with the protozoan Trypanosoma cruzi. The infection is transmitted by triatomine insects while blood feeding on a human host. Field studies predict that one third of an estimated 18 million T cruzi-infected humans in Latin America will die of Chagas disease. Acute infections are usually asymptomatic, but the ensuing chronic T cruzi infections have been associated with high ratios of morbidity and mortality: Chagas heart disease leads to unexpected death in 37.5% of patients, 58% develop heart failure and die and megacolon or megaoesophagus has been associated with death in 4.5%. The pathogenesis of Chagas disease appears to be related to a parasite-induced mutation of the vertebrate genome. Currently, treatment is unsatisfactory.

Clinical detection of depression among community-based elderly people with self-reported symptoms of depression.

BACKGROUND: Depression is under-diagnosed and under-treated in the primary care sector. The purpose of this study was to determine the association between self-reported indications of depression by community-dwelling elderly enrollees in a managed care organization and clinical detection of depression by primary care clinicians. METHODS: This was a 2-year cohort study of elderly people (n = 3410) who responded to the Geriatric Depression Scale (GDS) at the midpoint of the study period. A broad measure of clinical detection was used consisting of one or more of three indicators: diagnosis of depression, visit to a mental health specialist, or antidepressant medication treatment. RESULTS: Approximately half of the community-based elderly people with self-reported indications of depression (GDS > or = 11) did not have documentation of clinical detection of depression by health providers. Physician recognition of depression tended to increase with the severity of enrollees' self-reported feelings of depression. Men 65-74 years old and those > or = 85 years old were at highest risk for under-detection of depression by primary care providers. CONCLUSIONS: Clinical detection of depression of elderly people living in the community continues to be a problem. The implications of failure to recognize the possibility of depression among elderly White men suggest a serious public health problem.

Progressive chronic Chagas heart disease ten years after treatment with anti-Trypanosoma cruzi nitroderivatives.

A randomized ten-year follow-up study involving 91 Chagas patients and 41 uninfected controls was undertaken to determine the effectiveness of nitroderivative therapy. Anti-Trypanosoma cruzi antibodies were consistently lower one year after treatment than 10 years thereafter (P < 0.001). The blood of all treated and 93.7% of untreated Chagas patients yielded polymerase chain reaction (PCR) product from probes annealing to T. cruzi nuclear DNA, indicating active infection. Competitive PCR showed means +/- standard deviations of 20.1+/-22.6 T. cruzi/ml of blood from untreated and 13.8+/-14.9 from treated Chagas patients, but the differences between means were not statistically significant (P > 0.05). Electrocardiograms recorded a gamut of alterations several-fold more frequent in Chagas patients, regardless of treatment, than in uninfected controls (P < 0.001). These results show that nitroderivative therapy for T. cruzi infections is unsatisfactory and cannot be recommended since it fails to eradicate the parasite or change the progression of heart disease in chronic Chagas patients.

The role of depression in the association between self-rated physical health and clinically defined illness.

We enrolled 543 elderly participants of a managed care organization in a cross-sectional study to test whether the association between self-rated physical health and clinically defined illness differs for persons who are not depressed compared with persons with minor or serious depression. Depression was measured with the Diagnostic Interview Schedule (DIS). Clinically defined illness was measured with the Chronic Disease Score (CDS), a pharmacy-based measure. Additional variables included age, sex, and self-reported pain and physical function. Self-rated physical health was associated with both minor and serious depression, independent of clinically defined illness; minor depression was no longer significant when self-reported pain and physical function were added to the model. A significant negative correlation between self-rated physical health and clinically defined illness was observed for minor and no depression, but no correlation was seen for serious depression. These results confirm the association between depression and self-rated physical health and emphasize that, for persons with serious depression, self-rated health provides a less accurate picture of clinically defined illness at both ends of the spectrum. Also, a diagnosis of minor depression should not forestall investigation of inconsistencies between patient report and clinical evidence.

Blood-sucking lice may disseminate Trypanosoma cruzi infection in baboons.

Trypanosoma cruzi (Schyzotrypanum, Chagas, 1909), and Chagas disease are endemic in captive-reared baboons at the Southwest Foundation for Biomedical Research, San Antonio, Texas. We obtained PCR amplification products from DNA extracted from sucking lice collected from the hair and skin of T. cruzi-infected baboons, with specific nested sets of primers for the protozoan kinetoplast DNA, and nuclear DNA. These products were hybridized to their complementary internal sequences. Selected sequences were cloned and sequencing established the presence of T. cruzi nuclear DNA, and minicircle kDNA. Competitive PCR with a kDNA set of primers determined the quantity of approximately 23.9 +/- 18.2 T. cruzi per louse. This finding suggests that the louse may be a vector incidentally contributing to the dissemination of T. cruzi infection in the baboon colony.

Antihypertensive medication changes and blood pressure goal achievement in a managed care population.

This study examined achievement of blood pressure (BP) goals, changes in antihypertensive therapy and reasons for these changes among adults with hypertension initiating angiotensin-converting enzyme inhibitors (ACEIs), angiotensin receptor blockers (ARBs) or calcium channel blockers (CCBs). Claims data were examined for changes to medication regimens. Patient charts for 501 patients provided BP levels and reasons for changing medications. BP goal achievement was highest for initiators of ARBs (81.4%), compared with ACEIs (75.5%; P=NS) and CCBs (68.9%; P<0.01). Changes in antihypertensive therapy were least likely among ARB recipients (59.9%) compared with ACEIs (71.86%; P=0.02) and CCBs (74.85%; P<0.01). Failure to achieve BP goals was the most common reason for change in therapy (ARB, 32.9%; ACEI, 42.5%, P=NS; CCB, 47.9%, P<0.01). Although most patients achieved target BP goals, many required changes in treatment regimens. Initial choice of antihypertensive therapy may mitigate changes in therapies and better achieve BP goals.

Integration of Trypanosoma cruzi kDNA minicircle sequence in the host genome may be associated with autoimmune serum factors in Chagas disease patients.

Integration of kDNA sequences within the genome of the host cell shown by PCR amplification with primers to the conserved Trypanosoma cruzi kDNA minicircle sequence was confirmed by Southern hybridization with specific probes. The cells containing the integrated kDNA sequences were then perpetuated as transfected macrophage subclonal lines. The kDNA transfected macrophages expressed membrane antigens that were recognized by antibodies in a panel of sera from ten patients with chronic Chagas disease. These antigens barely expressed in the membrane of uninfected, control macrophage clonal lines were recognized neither by factors in the control, non-chagasic subjects nor in the chagasic sera. This finding suggests the presence of an autoimmune antibody in the chagasic sera that recognizes auto-antigens in the membrane of T. cruzi kDNA transfected macrophage subclonal lines.