Variations in helminth faecal egg counts in Kato-Katz thick smears and their implications in assessing infection status with Schistosoma mansoni

Examination of stool specimens by Kato-Katz (K-K) thick smears is the standard method recommended by the WHO for field diagnosis of intestinal schistosomiasis. However, there is increasing concern that this technique has low diagnostic sensitivity. In 326 study subjects, we compared the diagnostic yield of examining one, three or five Kato-Katz thick smears prepared from one stool specimen using 41.7 mg templates. In a subset of 169 subjects who had no demonstrable Schistosoma mansoni eggs in their first three Kato-Katz thick smears, we assessed the comparative advantage of examining an additional three Kato-Katz thick smears from another stool specimen, taken four weeks later, to that of cumulative yield obtained by examining all five Kato-Katz thick smears derived from the first stool specimen. For all helminth infections, single Kato-Katz thick smear-based prevalence estimates were significantly lower than those obtained from triplet or quintet Kato-Katz thick smears. Prevalence of S. mansoni infection based on single, triplet and quintet Kato-Katz thick smears from one stool specimen were 31.3%, 45.7% and 52.1%, respectively. Prevalence estimate of S. mansoni based on quintet Kato-Katz thick smears from the first day stool specimens was not different from cumulative estimate obtained with two triplet Kato-Katz thick smears from two stool specimens, 52.1% and 52.8%, respectively. In conclusion, either examination of quintet Kato-Katz thick smears from one stool specimen using 41.7 mg template or initial triplet Kato-Katz thick smears from one stool specimen, and if these are negative, followed by examination of additional triplet Kato-Katz thick smears from subsequent day stool specimen can adequately assess individuals for infection status with S. mansoni.     

Brain structural correlates of upward social mobility in ethnic minority individuals

Purpose

Perigenual anterior cingulate cortex (pACC) is a neural convergence site for social stress-related risk factors for mental health, including ethnic minority status. Current social status, a strong predictor of mental and somatic health, has been related to gray matter volume in this region, but the effects of social mobility over the lifespan are unknown and may differ in minorities. Recent studies suggest a diminished health return of upward social mobility for ethnic minority individuals, potentially due to sustained stress-associated experiences and subsequent activation of the neural stress response system.

Methods

To address this issue, we studied an ethnic minority sample with strong upward social mobility. In a cross-sectional design, we examined 64 young adult native German and 76 ethnic minority individuals with comparable sociodemographic attributes using whole-brain structural magnetic resonance imaging.

Results

Results showed a significant group-dependent interaction between perceived upward social mobility and pACC gray matter volume, with a significant negative association in the ethnic minority individuals. Post-hoc analysis showed a significant mediation of the relationship between perceived upward social mobility and pACC volume by perceived chronic stress, a variable that was significantly correlated with perceived discrimination in our ethnic minority group.

Conclusion

Our findings extend prior work by pointing to a biological signature of the “allostatic costs” of socioeconomic attainment in socially disadvantaged upwardly mobile individuals in a key neural node implicated in the regulation of stress and negative affect.

     

The performance of direct agglutination tests (DAT) in the diagnosis of visceral leishmaniasis among Ethiopian patients with HIV co-infection

The incidence of visceral leishmaniasis (VL) in Ethiopia has dramatically increased over the last 10 years, coinciding with the advent of the HIV epidemic. HIV co-infection in VL patients results in atypical, clinical and serological presentations, and may hamper serological diagnosis of VL. The performance of direct agglutination tests (DAT) in the diagnosis of VL in 103 Ethiopian patients with or without HIV infection was therefore investigated. The DAT results indicated that 96 of the patients had leishmanial infections, although amastigotes were only detected in samples from 91. Data on HIV status showed that 50.7% of all patients but 56.0% of the parasitologically confirmed cases of VL patients were HIV-positive. Based on the 95 patients who were each examined both by DAT and parasitological methods, the overall sensitivity of the DAT was 97.7%. Among the parasitologically confirmed cases of VL, a false-negative DAT result was obtained for two (3.9%) of the 51 cases who had HIV co-infection and for none of the 40 HIV-negative cases. In contrast to the observations made in Europe, DAT in Ethiopia therefore remain reasonably sensitive in the diagnosis of VL during HIV co-infection. The results are discussed in view of the possibility of distinctive antibody responses induced by Leishmania donovani donovani and L. d. infantum in HIV-infected patients.     

Prevalence of onchocercal skin disease and infection among workers of coffee plantation farms in Teppi,southwestern Ethiopia

In June 1996, a study on the economic impacts of onchocercal skin disease was initiated in southwestern Ethiopia. We made parasitological and clinicoepidemiological investigations among 1619 workers of a coffee plantation firm in Teppi, south-western Ethiopia. Sixty percent of the workers were included in the study. The prevalence of onchocercal skin disease (OSD) was 85.3%. Severe OSD (SOSD) was found in 17.3% of the study subjects. This was 1/5 of all OSD cases. The overall nodule carrier rate was 44.2%, which differed significantly by age classes from a rate of 12.3% to 73.0%. This rate varied by sex, 51.7% in males and 22.6% in females. Microfilarial carrier rate (MFCR) was 77.6%. This rate did not vary neither with severity of disease nor with presence or absence of pruritus or onchodermatitis. Mean microfilarial count was determined to be 38.1 per mg of skin snip or 44.4 per mg of infected skin snips. The geometric mean of microfilarial load per infected skin was 23.8. The community microfilarial load (CMFL) was estimated to be 14.0 per mg skin snip. The study showed that SOSD is prevalent in Teppi and affects a substantial number of the working population. An intervention program is called for.     

Epidemiological studies on intestinal schistosomiasis in Wondo Genet,southern Ethiopia

A cross-sectional epidemiological survey was made on intestinal schistosomiasis due to Schistosoma mansoni in Wondo Genet, southern Ethiopia, in 1999 to generate preintervention parasitological and malacological baseline data to be used as a reference in evaluation of community-based pilot control trial to be launched using wild-growing Endod. A total of 3000 stool specimens were collected from schoolchildren enrolled in 14 schools and microscopically examined using Kato method. The overall prevalence and intensity of schistosomiasis mansoni was 34.6% and 184 eggs per gram of stool (EPG), respectively. Children excreting Schistosoma mansoni eggs were found in all of the 14 schools surveyed with a prevalence of infection ranging from 1.9% in Abaye School to 80.6% in Shesha Kekele School. The overall prevalence of S. mansoni infection among males and females was 38.4% and 27.3%, respectively (P = 0.0001, 95% C.I = 7.5%-14.7%) where as the intensity of infection was 186 EPG and 181 EPG, respectively (P = 0.8045, 95% C.I = 1.17%-1.23%). Malacological surveys of 27 water contact sites revealed the occurrence of Biomphalaria pfeifferi in 8 sites out of which 3 harbored infected snails shedding schistosome cercariae. The necessity for initiating community-based sustainable control programme is discussed.     

Distinct immunity in patients with visceral leishmaniasis from that in subclinically infected and drug-cured people: implications for the mechanism underlying drug cure

Significant levels of IgG3 and IgG4 and high levels of IgG1 leishmania-specific antibody differentiated the immune states in 10 patients with visceral leishmaniasis from those of virtually all 20 drug-cured and 18 subclinically infected subjects, whereas the level of IgG2 antibody was nondiscriminating. The most extreme "subclinically infected" outlier subsequently developed disease. Overall, the immune states in subclinically infected and drug-cured persons were mutually indistinguishable but were readily distinguished from those of patients. These findings may have implications for the immunologic mechanism underlying drug cure in visceral leishmaniasis.     

"Home treatment" for mental illness. Concept definition and effectiveness

A number of projects have used home treatment (HT) for severely mentally ill people in recent years. This paper intends to define HT and show the main differences between it and other forms of psychiatric community service, present the existing evidence for HT, and discuss eligibility criteria. Studies about HT's efficacy in treating severely mentally ill adults were identified by electronic (MEDLINE, PsycLIT) and manual search. Six studies met these inclusion criteria. Compared to inpatient treatment, HT was equally or more efficacious in respect to reduction of symptom distress, social (re-)integration, and patient and carer satisfaction. Furthermore, direct costs for HT were often lower than for inpatient care. However, the number of relevant studies is limited and knowledge on the long-term effects of HT is sparse.     

Treatment of intestinal worms is associated with decreased HIV plasma viral load

BACKGROUND: We have previously suggested that helminthic infections make the host more susceptible to HIV infection and enhance its progression due to the chronic immune activation they cause. OBJECTIVE: To study the effect of antihelminthic treatment on HIV plasma viral load (VL) in HIV- and helminth-infected individuals living in Ethiopia. METHODS: Fifty-six clinically asymptomatic HIV-1-infected individuals, 31 (55%) of whom were also infected with helminths, were studied. All participants received antihelminthic treatment at baseline and at 3 and 6 months. Worm egg excretion, HIV plasma VL, and T-cell subsets were determined at baseline and 6 months after treatment. RESULTS: The mean age, number of CD4 T cells, and gender distribution were similar in the helminth-infected and -noninfected groups. At baseline, HIV plasma VL was strongly correlated to the number of eggs excreted (p <.001) and was higher in individuals infected with more than one helminth (5.28 +/- 0.35 versus 4.30 +/- 1.13 log RNA copies/mL, respectively; p =.16). After treatment of helminths, the 6-month change in HIV plasma VL was significantly different between the successfully treated group and the persistently helminth-positive group (p =.04) CONCLUSIONS: Helminth "load" is correlated to HIV plasma VL, and successful deworming is associated with a significant decrease in HIV plasma VL. The results of the current study, if confirmed in a larger study, may have important implications for slowing disease progression and reducing risks of transmission.     

Emerging Leishmania/HIV co-infection in Africa

The HIV/AIDS pandemic is spreading at an alarmingly high rate in Africa. Leishmaniasis is also highly prevalent in the continent. Despite the emergence of Leishmania/HIV co-infection in Africa, the numbers reported are disproportionately low. Moreover, the number of cases of co-infection is expected to rise in Africa owing to the simultaneous spread of the two infectious diseases and their increasingly overlapping geographical distribution.