Swansea University

Fungus could control mosquitoes

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Fungus could control mosquitoes, research suggests

mosquito
The fungus occurs in soil and kills a whole range of insects

Researchers at Swansea University say a fungus could be the key to controlling mosquitoes.

Fungus Metarhizium anisopliae lives in soil and kills a whole range of insects and researchers say it also affects mosquito larvae if added to the water where the insect breeds.

The insects carry diseases such as yellow fever and malaria.

According to the World Health Organisation malaria causes 800,000 deaths a year world-wide.

The team at Swansea University’s department of bioscience said initial trials are very promising.

“The fungus occurs in soil and kills a whole range of insects but we’ve put it in the water where mosquito larvae breed and it is ingested by the insect and they die,” team member Professor Tariq Butt told BBC Radio Wales.

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It’s quite nice that we’re killing three of the major species of mosquito transmitting a whole range of diseases”

Prof Tariq Butt Swansea University

“Normally what happens is the fungus attaches to its hosts, germinates and penetrates the body of the insect, colonises the insect and in the process the insect dies.

“But, in this case it doesn’t germinate it just stays as spores packed in the body, in the gut, of the insect where it causes stress which activates a number of genes which trigger a whole range of responses leading to the death of the insect.”

Malaria and yellow fever

Further research is now needed to see how the fungus can be introduced as initially it was hoped it would be passed from one insect to another, he added.

 “In the past we were hoping the fungus was going to emerge from the body of the insect then the spores would be carried over to the healthy larvae and create an epidemic, but now what we’re seeing is we’d have to apply the fungus frequently,” he added.

The hope is the research will find a way to control the insect which spreads diseases such as malaria and yellow fever.

“It is reported that 300 children die each hour in Africa because of Malaria, but other diseases which are emerging such as dengue (fever) results in thousands of deaths reported across the world and also some of these diseases have been reported in Europe,” said Prof Butt.

“We’ve done a number of trials and it looks very, very promising. Also, it’s quite nice that we’re killing three of the major species of mosquito transmitting a whole range of diseases.”

Probiotics Do Not Reduce Diarrhea Risk in Large Trial.

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Probiotic supplements did not prevent antibiotic-associated diarrhea (AAD) or Clostridium difficile diarrhea (CDD) in a large randomized, double-blind, placebo-controlled trial.

Stephen J. Allen, MD, from Swansea University, United Kingdom, and colleagues reported the results in an article published onlineAugust 8 in the Lancet.

The researchers recruited patients 65 years or older to the Probiotic lactobacilli and bifidobacteria in antibiotic-associated diarrhoea andClostridium difficile diarrhoea in the elderly (PLACIDE) trial if they were exposed to 1 or more oral or parenteral antibiotics in the preceding 7 days or were about to begin antibiotic therapy. Participants were enrolled from 5 hospitals between December 1, 2008, and February 28, 2012, and were excluded if there were existing diarrhea or CDD in the previous 3 months, significant immune system compromise, any illness requiring intensive care, prosthetic heart valve, or underlying gastrointestinal disease. The primary study outcomes were the occurrence of AAD within 8 weeks of recruitment and CDD within 12 weeks of recruitment.

Overall, 1493 patients were randomly assigned to the microbial preparation group and 1488 to the placebo group. Of those, the researchers included 1470 and 1471, respectively, in the primary-endpoint analyses. Antibiotic exposure was similar between the 2 groups. The probiotic preparation consisted of a capsule containing 2 strains of Lactobacillus acidophilus and 2 strains of bifidobacterium.

The researchers found no difference between the groups in the incidence of ADD (including CDD). In the probiotics group,159 (10.8%) patients developed ADD compared with 153 (10.4%) patients in the placebo group (relative risk [RR], 1.04; 95% confidence interval [CI], 0.84 – 1.28; P = 0.71).

The study authors also found that CDD was an uncommon cause of ADD, occurring in only 12 (0.8%) participants in the microbial preparation group and 17 (1.2%) participants in the placebo group (RR, 0.71; 95% CI, 0.34-1.47; P = 0.35).

“Our trial suggests that properties common to many so-called probiotic bacteria, such as the production of lactic acid, are not effective against AAD in older inpatients,” write Dr. Allen and colleagues.

Although the authors note that this “is the largest trial so far for this problem,” they acknowledge study weaknesses such as low ethnic diversity and lack of participation by eligible patients resulting from an unwillingness to take an additional preparation.

“Our findings do not provide statistical evidence to support recommendations for the routine use of microbial preparations for the prevention of AAD and CDD,” conclude the study authors.

In an accompanying editorial, Nick Daneman, MD, FRCPC, from the University of Toronto, Ontario, Canada, points out that recent meta-analyses have shown large positive effects with the use of probiotic supplements. He also notes that statistical variations such as a low event rate in the current study and overlapping confidence intervals between this study and the meta-analysis may account for the differing results.

However, the size of the current study “dwarfs” previous studies, most of which, he says, were small single institution efforts. “PLACIDE is a large and rigorous negative study, and we must judge whether it can tip the balance of probiotic evidence,” he writes.

“At the very least, the low absolute risk reductions in PLACIDE question the cost-effectiveness of probiotics,” writes Dr. Daneman. In addition, “lactobacilli and bifidobacteria are only two types of non­pathogenic bacteria, and we must consider whether they can really tip the balance of a diverse gut ecosystem,” he concludes.

Funding for this study was provided by the Health Technology Assessment program of the National Institute for Health Research, with additional funding provided by the County Durham and Tees Valley, National Institute for Health Research Comprehensive Local Research Network. Dr. Allen has done research in probiotics supported by Cultech, UK; has been an invited guest at the Yakult Probiotic Symposium; and has received research funding from Yakult, UK. The other authors and the editorialist have disclosed no relevant financial relationships.

Source: Lancet.

 

 

 

Source: Medscape.com