Resistant starch from high amylose maize (HAM‐RS2) reduces body fat and increases gut bacteria in ovariectomized (OVX) rats

Objective:

Obesity after menopause is a health concern for older females. Changes in the microbiota are likely to occur with this condition. Modifying the microbiota with a prebiotic is a plausible strategy for improving the health of menopausal females.

Design and Methods:

Resistant starch type 2 from high‐amylose maize (HAM‐RS2) was used as a prebiotic in rats in a 2 × 2 factorial study with two levels of HAM‐RS2 (0 or 29.7% of weight of diet) referred to as energy control (EC) and HAM‐RS2 diets, respectively; and two levels of surgery, ovariectomized (OVX) and sham.

Results:

In a 6‐week, postsurgery recovery period, OVX rats gained more body weight with consumption of a similar amount of food. Subsequently, consumption of HAM‐RS2 versus EC diets resulted in reduced abdominal fat in both OVX and sham rats; but when normalized for disemboweled body weight (body weight minus GI tract), there was no effect of surgery, only reduction with HAM‐RS2. Targeted bacterial populations were estimated that are known to ferment HAM‐RS2 or metabolize the products of that initial fermentation. OVX and sham rats demonstrated increased bacterial levels with dietary HAM‐RS2 for all bacteria. Additionally, culture techniques and qPCR provided similar results.

Conclusion:

This study shows that, as expected, OVX increases adiposity. However, contrary to previous effects seen in obese mice, this did not prevent fermentation of HAM‐RS2 and consequently, the fat gain associated with OVX was attenuated.     

Proof-of-Principle of Onchocerciasis Elimination with Ivermectin Treatment in Endemic Foci in Africa: Final Results of a Study in Mali and Senegal

Background

Mass treatment with ivermectin controls onchocerciasis as a public health problem, but it was not known if it could also interrupt transmission and eliminate the parasite in endemic foci in Africa where vectors are highly efficient. A longitudinal study was undertaken in three hyperendemic foci in Mali and Senegal with 15 to 17 years of annual or six-monthly ivermectin treatment in order to assess residual levels of infection and transmission, and test whether treatment could be safely stopped. This article reports the results of the final evaluations up to 5 years after the last treatment.

Methodology/Principal Findings

Skin snip surveys were undertaken in 131 villages where 29,753 people were examined and 492,600 blackflies were analyzed for the presence of Onchocerca volvulus larva using a specific DNA probe. There was a declining trend in infection and transmission levels after the last treatment. In two sites the prevalence of microfilaria and vector infectivity rate were zero 3 to 4 years after the last treatment. In the third site, where infection levels were comparatively high before stopping treatment, there was also a consistent decline in infection and transmission to very low levels 3 to 5 years after stopping treatment. All infection and transmission indicators were below postulated thresholds for elimination.

Conclusion/Significance

The study has established the proof of principle that onchocerciasis elimination with ivermectin treatment is feasible in at least some endemic foci in Africa. The study results have been instrumental for the current evolution from onchocerciasis control to elimination in Africa.     

Significantly reduced intensity of infection but persistent prevalence of schistosomiasis in a highly endemic region in mali after repeated treatment

Background

Preventive chemotherapy against schistosomiasis has been implemented since 2005 in Mali, targeting school-age children and adults at high risk. A cross-sectional survey was conducted in 2010 to evaluate the impact of repeated treatment among school-age children in the highly-endemic region of Segou.

Methodology/Principal Findings

The survey was conducted in six sentinel schools in three highly-endemic districts, and 640 school children aged 7–14 years were examined. Infections with Schistosoma haematobium and S. mansoni were diagnosed with the urine filtration and the Kato-Katz method respectively. Overall prevalence of S. haematobium infection was 61.7%, a significant reduction of 30% from the baseline in 2004 (p<0.01), while overall prevalence of S. mansoni infection was 12.7% which was not significantly different from the baseline. Overall mean intensity of S. haematobium and S. mansoni infection was 180.4 eggs/10 ml of urine and 88.2 epg in 2004 respectively. These were reduced to 33.2 eggs/10 ml of urine and 43.2 epg in 2010 respectively, a significant reduction of 81.6% and 51% (p<0.001). The proportion of heavy S. haematobium infections was reduced from 48.8% in 2004 to 13.8% in 2010, and the proportion of moderate and heavy S. mansoni infection was reduced from 15.6% in 2004 to 9.4% in 2010, both significantly (p<0.01). Mathematical modelling suggests that the observed results were in line with the expected changes.

Conclusions/Significance

Significant reduction in intensity of infection on both infections and modest but significant reduction in S. haematobium prevalence were achieved in highly-endemic Segou region after repeated chemotherapy. However, persistent prevalence of both infections and relatively high level of intensity of S. mansoni infection suggest that more intensified control measures be implemented in order to achieve the goal of schistosomiasis elimination. In addition, closer monitoring and evaluation activities are needed in the programme to monitor the drug tolerance and to adjust treatment focus.     

First detection of Leishmania major DNA in Sergentomyia (Spelaeomyia) darlingi from cutaneous leishmaniasis foci in Mali

Background

Leishmania major complex is the main causative agent of zoonotic cutaneous leishmaniasis (ZCL) in the Old World. Phlebotomus papatasi and Phlebotomus duboscqi are recognized vectors of L. major complex in Northern and Southern Sahara, respectively. In Mali, ZCL due to L. major is an emerging public health problem, with several cases reported from different parts of the country. The main objective of the present study was to identify the vectors of Leishmania major in the Bandiagara area, in Mali.

Methodology/Principal Findings

An entomological survey was carried out in the ZCL foci of Bandiagara area. Sandflies were collected using CDC miniature light traps and sticky papers. In the field, live female Phlebotomine sandflies were identified and examined for the presence of promastigotes. The remaining sandflies were identified morphologically and tested for Leishmania by PCR in the ITS2 gene. The source of blood meal of the engorged females was determined using the cyt-b sequence. Out of the 3,259 collected sandflies, 1,324 were identified morphologically, and consisted of 20 species, of which four belonged to the genus Phlebotomus and 16 to the genus Sergentomyia. Leishmania major DNA was detected by PCR in 7 of the 446 females (1.6%), specifically 2 out of 115 Phlebotomus duboscqi specimens, and 5 from 198 Sergentomyia darlingi specimens. Human DNA was detected in one blood-fed female S. darlingi positive for L. major DNA.

Conclusion

Our data suggest the possible involvement of P. duboscqi and potentially S. darlingi in the transmission of ZCL in Mali.     

Implementing preventive chemotherapy through an integrated National Neglected Tropical Disease Control Program in Mali

Background

Mali is endemic for all five targeted major neglected tropical diseases (NTDs). As one of the five ‘fast-track’ countries supported with the United States Agency for International Development (USAID) funds, Mali started to integrate the activities of existing disease-specific national control programs on these diseases in 2007. The ultimate objectives are to eliminate lymphatic filariasis, onchocerciasis and trachoma as public health problems and to reduce morbidity caused by schistosomiasis and soil-transmitted helminthiasis through regular treatment to eligible populations, and the specific objectives were to achieve 80% program coverage and 100% geographical coverage yearly. The paper reports on the implementation of the integrated mass drug administration and the lessons learned.

Methodology/Principal Findings

The integrated control program was led by the Ministry of Health and coordinated by the national NTD Control Program. The drug packages were designed according to the disease endemicity in each district and delivered through various platforms to eligible populations involving the primary health care system. Treatment data were recorded and reported by the community drug distributors. After a pilot implementation of integrated drug delivery in three regions in 2007, the treatment for all five targeted NTDs was steadily scaled up to 100% geographical coverage by 2009, and program coverage has since been maintained at a high level: over 85% for lymphatic filariasis, over 90% for onchocerciasis and soil-transmitted helminthiasis, around 90% in school-age children for schistosomiasis, and 76–97% for trachoma. Around 10 million people have received one or more drug packages each year since 2009. No severe cases of adverse effects were reported.

Conclusions/Significance

Mali has scaled up the drug treatment to national coverage through integrated drug delivery involving the primary health care system. The successes and lessons learned in Mali can be valuable assets to other countries starting up their own integrated national NTD control programs.