Natural and within-farmland biodiversity enhances crop productivity

Ongoing expansion of large-scale agriculture critically threatens natural habitats and the pollination services they offer. Creating patches with high plant diversity within farmland is commonly suggested as a measure to benefit pollinators. However, farmers rarely adopt such practice, instead removing naturally occurring plants (weeds). By combining pollinator exclusion experiments with analysis of honeybee behaviour and flower-visitation webs, we found that the presence of weeds allowed pollinators to persist within sunflower fields, maximizing the benefits of the remaining patches of natural habitat to productivity of this large-scale crop. Weed diversity increased flower visitor diversity, hence ameliorating the measured negative effects of isolation from natural habitat. Although honeybees were the most abundant visitors, diversity of flower visitors enhanced honeybee movement, being the main factor influencing productivity. Conservation of natural patches combined with promoting flowering plants within crops can maximize productivity and, therefore, reduce the need for cropland expansion, contributing towards sustainable agriculture.     

Modulation of Anopheles gambiae Epsilon glutathione transferase activity by plant natural products in vitro

Elevated glutathione transferase (GST) E2 activity is associated with DDT resistance in the mosquito Anopheles gambiae. The search for chemomodulators that inhibit the function of AgGSTE2 would enhance the insecticidal activity of DDT. Therefore, we examined the interaction of novel natural plant products with heterologously expressed An. gambiae GSTE 2 in vitro. Five of the ten compounds, epiphyllocoumarin (Tral-1), knipholone anthrone, isofuranonaphthoquinones (Mr 13/2, Mr13/4) and the polyprenylated benzophenone (GG1) were shown to be potent inhibitors of AgGSTE2 with IC(50) values of 1.5 microM, 3.5 microM, 4 microM, 4.3 microM and 4.8 microM respectively. Non-competitive inhibition was obtained for Tral 1 and GG1 with regards to GSH (K(i) of 0.24 microM and 0.14 microM respectively). Competitive inhibition for Tral1 was obtained with CDNB (K(i) = 0.4 microM) whilst GG1 produced mixed type of inhibition. The K(i) and K(i)' for GSH for Tral-1 and GG1 were 0.2 microM and 0.1 microM respectively. These results suggest that the novel natural plant products, particularly Tral-1, represent potent AgGSTE2 in vitro inhibitors.     

A Venue-Based Survey of Malaria,Anemia and Mobility Patterns among Migrant Farm Workers in Amhara Region,Ethiopia

Background

Mobile populations present unique challenges to malaria control and elimination efforts. Each year, a large number of individuals travel to northwest Amhara Region, Ethiopia to seek seasonal employment on large-scale farms. Agricultural areas typically report the heaviest malaria burden within Amhara thereby placing migrants at high risk of infection. Yet little is known about these seasonal migrants and their malaria-related risk factors.

Methods and Findings

In July 2013, a venue-based survey of 605 migrant laborers 18 years or older was conducted in two districts of North Gondar zone, Amhara. The study population was predominantly male (97.7%) and young (mean age 22.8 years). Plasmodium prevalence by rapid diagnostic test (RDT) was 12.0%; One quarter (28.3%) of individuals were anemic (hemoglobin <13 g/dl). Nearly all participants (95.6%) originated from within Amhara Region, with half (51.6%) coming from within North Gondar zone. Around half (51.2%) slept in temporary shelters, while 20.5% regularly slept outside. Only 11.9% of participants had access to a long lasting insecticidal net (LLIN). Reported net use the previous night was 8.8% overall but 74.6% among those with LLIN access. Nearly one-third (30.1%) reported having fever within the past two weeks, of whom 31.3% sought care. Cost and distance were the main reported barriers to seeking care. LLIN access (odds ratio [OR] = 0.30, P = 0.04) and malaria knowledge (OR = 0.50, P = 0.02) were significantly associated with reduced Plasmodium infection among migrants, with a similar but non-significant trend observed for reported net use the previous night (OR = 0.16, P = 0.14).

Conclusions

High prevalence of malaria and anemia were observed among a young population that originated from relatively proximate areas. Low access to care and low IRS and LLIN coverage likely place migrant workers at significant risk of malaria in this area and their return home may facilitate parasite transport to other areas. Strategies specifically tailored to migrant farm workers are needed to support malaria control and elimination activities in Ethiopia.     

Causes of Death among Adults in Northern Ethiopia: Evidence from Verbal Autopsy Data in Health and Demographic Surveillance System

Background

In countries where registration of vital events is lacking and the proportion of people who die at home without medical care is high, verbal autopsy is used to determine and estimate causes of death.

Methods

We conducted 723 verbal autopsy interviews of adult (15 years of age and above) deaths from September 2009 to January 2013. Trained physicians interpreted the collected verbal autopsy data, and assigned causes of death according to the international classification of diseases (ICD-10). We did analysis of specific as well as broad causes of death (i.e. non-communicable diseases, communicable diseases and external causes of death) by sex and age using Stata version 11.1. We performed logistic regression to identify socio-demographic predictors using odds ratio with 95% confidence interval and a p-value of 0.05.

Findings

Tuberculosis, cerebrovascular diseases and accidental falls were leading specific causes of death accounting for 15.9%, 7.3% and 3.9% of all deaths. Two hundred sixty three (36.4% [95% CI: 32.9, 39.9]), 252 (34.9% [95% CI: 31.4, 38.4]) and 89 (12.3% [95% CI: 10.1, 14.9]) deaths were due to non-communicable, communicable diseases, and external causes, respectively. Females had 1.5 times (AOR = 1.53 [95% CI: 1.10, 2.15]) higher odds of dying due to communicable diseases than males. The odds of dying due to external causes were 4 times higher among 15–49 years of age (AOR = 4.02 [95% CI: 2.25, 7.18]) compared to older ages. Males also had 1.7 times (AOR = 1.70 [95% CI: 1.01, 2.85]) higher odds of dying due to external causes than females.

Conclusion

Tuberculosis, cerebrovascular diseases and accidental falls were the top three causes of death among adults. Efforts to prevent tuberculosis and cerebrovascular diseases related deaths should be improved and safety efforts to reduce accidents should also receive attention.     

Concentration of Lymph Node Aspirate Improves the Sensitivity of Acid Fast Smear Microscopy for the Diagnosis of Tuberculous Lymphadenitis in Jimma,Southwest Ethiopia

Background

Tuberculous lymphadenitis (TBLN) is the most common form of extrapulmonary tuberculosis. The cytomorphological features of lymph node smears have reduced specificity for the diagnosis of tuberculosis. The diagnosis of TBLN with direct smear microscopy lacks sensitivity due to the limited number of bacilli in lymph node aspirate. Therefore, we aimed to assess whether the concentration of lymph node aspirate improves the sensitivity of acid fast smear microscopy for the diagnosis of tuberculous lymphadenitis.

Methods

A cross-sectional comparative study was conducted on 200 patients clinically suspected for tuberculous lymphadenitis in Jimma, Ethiopia. Lymph node aspirate was collected. The first two drops were used for cytomorphological study and direct acid fast staining. The remaining aspirate was treated with N-acetyl-L-cysteine (NALC) and concentrated by centrifugation at 3000 g for 15 minutes. The sediment was used for acid fast staining and culture. Differentiation of M. tuberculosis complex (MTBC) from non-tuberculous mycobacteria (NTM) was done by para-nitrobenzoic acid susceptibility test.

Result

Complete data were available for 187 study subjects. 68% (127/187) were positive for M. tuberculosis on culture. Four isolates, 2.1% (4/187), were identified as NTM. The detection rate of direct smear microscopy was 25.1% and that of the concentration method 49.7%. Cytomorphologically, 79.7% of cases were classified as TBLN. The sensitivity of direct smear microscopy was 34.6%, for concentrated smear microscopy 66.1%, and for cytomorphology 89.8%. Two AFB positive cases on concentration method were non-tuberculosis mycobacteria (NTM). The concentration method yielded a positive result from seven cases diagnosed as suppurative abscess by cytology. Both for the direct and concentration methods the highest rate of AFB positivity was observed in smears showing caseous necrosis alone. Smear positivity rate decreased with the appearance of epithelioid cell aggregates.

Conclusion

The concentration of lymph node aspirates for acid fast smear microscopy had significantly higher sensitivity than direct microscopy.     

Knowledge, health seeking behavior and perceived stigma towards tuberculosis among tuberculosis suspects in a rural community in southwest Ethiopia

Background

Perceived stigma and lack of awareness could contribute to the late presentation and low detection rate of tuberculosis (TB). We conducted a study in rural southwest Ethiopia among TB suspects to assess knowledge about and stigma towards TB and their health seeking behavior.

Methods

A community based cross sectional survey was conducted from February to March 2009 in the Gilgel Gibe field research area. Any person 15 years and above with cough for at least 2 weeks was considered a TB suspect and included in the study. Data were collected by trained personnel using a pretested structured questionnaire. Logistic regression analysis was done using SPSS 15.0 statistical software.

Results

Of the 476 pulmonary TB suspects, 395 (83.0%) had ever heard of TB; “evil eye” (50.4%) was the commonly mentioned cause of TB. Individuals who could read and write were more likely to be aware about TB [(crude OR = 2.98, (95%CI: 1.25, 7.08)] and more likely to know that TB is caused by a microorganism [(adjusted OR = 3.16, (95%CI: 1.77, 5.65)] than non-educated individuals. Males were more likely to know the cause of TB [(adjusted OR = 1.92, (95%CI: 1.22, 3.03)] than females. 51.3% of TB suspects perceived that other people would consider them inferior if they had TB. High stigma towards TB was reported by 199(51.2%). 220 (46.2%) did not seek help for their illness. Individuals who had previous anti-TB treatment were more likely to have appropriate health seeking behavior [(adjusted OR = 3.65, (95%CI: 1.89, 7.06)] than those who had not.

Conclusion

There was little knowledge about TB in the Gilgel Gibe field research area. We observed inappropriate health seeking behavior and stigma towards TB. TB control programs in Ethiopia should educate rural communities, particularly females and non-educated individuals, about the cause and the importance of early diagnosis and treatment of TB.     

The evaluation of novel natural products as inhibitors of human glutathione transferase P1-1

Glutathione transferase P1-1 is over expressed in some cancer cells and contributes to detoxification of anticancer drugs, leading to drug-resistant tumors. The inhibition of human recombinant GSTP1-1 by natural plant products was investigated using 10 compounds isolated from plants indigenous to Southern and Central Africa. Monochlorobimane and 1-chloro-2,4-dinitrobenzene were used to determine GST activity. Each test compound was screened at 33 and 100 μM. Isofuranonapthoquinone (1) (from Bulbine frutescens) showed 68% inhibition at 33 μM, and sesquiterpene lactone (2) (from Dicoma anomala) showed 75% inhibition at 33 μM. The IC(50) value of 1 was 6.8 μM. The mode of inhibition was mixed, partial (G site) and noncompetitive (H site) with K(i) values of 8.8 and 0.21 μM, respectively. Sesquiterpene 2 did not inhibit the CDNB reaction. Therefore, isofuranonapthoquinone 1 needs further investigations in vivo because of its potent inhibition of GSTP1-1 in vitro.     

Chemical constituents of Trilepisium madagascariense (Moraceae) and their antimicrobial activity

The chemical study of Trilepisium madagascariense has led to the isolation of two previously undescribed compounds, (+)-(2S)-7-hydroxy-3′,4′-dimethoxyflavan (trilepisflavan) and (E)-4-[3-(3,4-dihydroxyphenyl)prop-2-enoyloxy]-3-hydroxybenzoic acid (trilepisuimic acid), together with ten known compounds caffeic acid, catechin, erythrodiol-3-O-palmitate, 8-C-glucopyranosylapigenin, dihydrokaempferol, protocatechuic acid, 3′,7-dihydroxy-4′-methoxyflavan, isoliquiritigenin, luteolin and 1,3-dimethoxybenzene. Their structures were elucidated on the basis of spectroscopic evidence. Crude extracts, trilepisflavan, dihydrokaempferol and 8-C-glucopyranosylapigenin showed significant antimicrobial activity.     

Efficacy of Handwashing with Soap and Nail Clipping on Intestinal Parasitic Infections in School-Aged Children: A Factorial Cluster Randomized Controlled Trial

Background

Intestinal parasitic infections are highly endemic among school-aged children in resource-limited settings. To lower their impact, preventive measures should be implemented that are sustainable with available resources. The aim of this study was to assess the impact of handwashing with soap and nail clipping on the prevention of intestinal parasite reinfections.

Methods and Findings

In this trial, 367 parasite-negative school-aged children (aged 6–15 y) were randomly assigned to receive both, one or the other, or neither of the interventions in a 2 × 2 factorial design. Assignment sequence was concealed. After 6 mo of follow-up, stool samples were examined using direct, concentration, and Kato-Katz methods. Hemoglobin levels were determined using a HemoCue spectrometer. The primary study outcomes were prevalence of intestinal parasite reinfection and infection intensity. The secondary outcome was anemia prevalence. Analysis was by intention to treat. Main effects were adjusted for sex, age, drinking water source, latrine use, pre-treatment parasites, handwashing with soap and nail clipping at baseline, and the other factor in the additive model. Fourteen percent (95% CI: 9% to 19%) of the children in the handwashing with soap intervention group were reinfected versus 29% (95% CI: 22% to 36%) in the groups with no handwashing with soap (adjusted odds ratio [AOR] 0.32, 95% CI: 0.17 to 0.62). Similarly, 17% (95% CI: 12% to 22%) of the children in the nail clipping intervention group were reinfected versus 26% (95% CI: 20% to 32%) in the groups with no nail clipping (AOR 0.51, 95% CI: 0.27 to 0.95). Likewise, following the intervention, 13% (95% CI: 8% to 18%) of the children in the handwashing group were anemic versus 23% (95% CI: 17% to 29%) in the groups with no handwashing with soap (AOR 0.39, 95% CI: 0.20 to 0.78). The prevalence of anemia did not differ significantly between children in the nail clipping group and those in the groups with no nail clipping (AOR 0.53, 95% CI: 0.27 to 1.04). The intensive follow-up and monitoring during this study made it such that the assessment of the observed intervention benefits was under rather ideal circumstances, and hence the study could possibly overestimate the effects when compared to usual conditions.

Conclusions

Handwashing with soap at key times and weekly nail clipping significantly decreased intestinal parasite reinfection rates. Furthermore, the handwashing intervention significantly reduced anemia prevalence in children. The next essential step should be implementing pragmatic studies and developing more effective approaches to promote and implement handwashing with soap and nail clipping at larger scales.