Link Found Between Cholera Outbreaks And Rise Of River Flow

One mystery resolved on cholera by examination of four major river basins – including the Ganges, Brahmaputra, Meghna, Congo, Amazon and Orinoco in South America – finds when water flow rose, nutrients in the water were associated with increase in cholera cases

Published on August 3rd in the American Journal of Tropical Medicine and Hygiene – A new study revealed, an investigation of the biggest river basins in the world discovered, nutrient-rich and powerful discharges led to spikes in the blooms of plankton linked with cholera outbreaks. These raised discharges frequently take place at times when coastal water temperature is increased, implying that it will be more complicated than first believed in predicting global warming’s potential temperature effect on cholera.

These findings will help give public health authorities another essential clue in predicting outbreaks in the future of cholera, based on climatic and environmental models, in the aspiration of stopping the expansion of the lethal and highly infectious disease that presently curses Haiti and several other countries.

The researchers started in the Bay of Bengal, where their goal was to solve a puzzle : When sea temperatures rise, phytoplankton – microscopic plants in the ocean that provide a food source for zooplankton, which cholera bacteria are linked with – decreases. So why did previous investigations find sea temperatures rising and numbers of phytoplankton also increasing? They analyzed twelve years of data, together with images from NASA satellites, and highlighted the large flows from the Ganges, Brahmaputra and Meghna rivers, transporting nutrients from soil as the reason for bloom in phytoplankton, followed by zooplankton which contributes to outbreaks of cholera.

Shafiqul Islam, PhD, the lead researcher of the study, a professor in the Department of Civil and Environmental Engineering and at the Fletcher School of Law and Diplomacy at Tufts University in Medford/Somerville, Massachusetts, says,

“We weren’t satisfied with just this result, so we then went to test this finding in other places – the Orinoco (in South America), the Congo, and the Amazon river basins, and we found the same thing: The positive relationship between phytoplankton blooms and ocean temperature is related to large river discharges.

The main significance is that finding an association between sea surface temperatures and cholera outbreaks should not lead us to conclude that with global warming, cholera will definitely go up.”

Islam said however, that global warming might play a role in alternative ways in outbreaks of cholera,
together with contributing to droughts and high salinity intrusion in the dry season and floods in the wet season. Published recently in the journal Water Resources, both of those conditions have been discovered to also contribute to cholera epidemics.

“If river flows are more turbulent, if droughts are more severe, if flood is more severe, cholera is more severe, but cholera may not have direct linkage with rising sea surface temperatures.”

Bacterium Vibrio cholerae, which produces a toxin that causes severe diarrhea, is the cause of Cholera. Most common in areas with poor sanitation, crowding, and social instability, Cholera creates extreme fear due to the sudden onset of diarrhea with the potential for a high number of deaths.

Nine months ago in the Democratic Republic of Congo, a furious cholera outbreak has killed hundreds and sickened over 100,000 people, the World Health Organization reported in July. Since the rainy season started this spring, Haiti is seeing a new upsurge in cholera cases. Beginning in October 2010 the epidemic has caused illness in over 300,000 people, killing nearly 5,000.

Rita R. Colwell, PhD, co-author of the investigation and a professor at both the University of Maryland and the John Hopkins Bloomberg School of Public Health explained,

“We don’t know for sure if Haiti’s cholera outbreak is related to its river system, but its rivers were severely impacted by the earthquake, It’s a system we should study in Haiti. I’m intrigued to see this relationship between cholera and river flow. It gives us much more detail about what can trigger cholera outbreak.”

Peter J Hotez, MD, PhD, President, American Society of Tropical Medicine and Hygiene said the investigation underscored the “complex ecology associated with cholera,” adding that researchers work is understanding cholera outbreaks is critically important now.

Hotez said.

“Cholera seems to be gaining a foothold in more places than it used to be. We used to see shorter outbreaks, but in Africa, and now in Haiti, we’re seeing nationwide epidemics lasting months or more than a year. We obviously need to be taking a different approach.”

Grace Rattue

Continue reading

Managing Substance Abuse And HIV In Malaysia

In a significant change of policy, the Malaysian government now has authority for providing medical treatment for heroin
dependence and related health conditions. Evidence shows that treating addiction and drug abuse with such
medications as naltrexone, buprenorphine, and methadone could help decrease the unusually high prevalence of HIV in
Malaysia.

Background: Despite consistent economic development and a respected primary health care system, Malaysia has the
second highest HIV prevalence among adults in the Western Pacific region and the highest proportion of HIV cases
resulting from injection drug abuse. By the end of 2004, as many as 234,000 heroin abusers had been registered in the
official Malaysian government registry, but there may be as many as 500,000 heroin abusers there. Drug abuse and related
disorders, such as HIV, exert a heavy burden on the country’s health care and legal systems. Historically, Malaysian drug
offenders were rehabilitated involuntarily in correctional, rather than health care, facilities. This approach had limited
effectiveness, which led to the recent introduction of medical treatments for addiction.

Study Design: The scientists reviewed the literature to determine the scope of heroin and other drug abuse in Malaysia;
treatment for heroin addiction and abuse of amphetamine-type stimulants; and the scope of HIV.

What They Found: In Malaysia, more than 30,000 opiate-dependent patients are currently treated with such medications
as naltrexone, buprenorphine, and methadone. Despite the high prevalence of HIV and other infectious diseases among
addicted people, few HIV prevention efforts have targeted Malaysian drug abusers, who represent only a minority of
patients receiving antiretroviral therapy.

Comments From The Authors: Malaysia has until recently lagged behind in the treatment of drug addiction and related
disorders, despite experiencing severe drug problems. Now, however, the Ministry of Health has authority for providing
medical treatment for heroin dependence. This shift signals a remarkable change in Malaysian policies and approaches to
addiction and an important opportunity to develop, implement, and disseminate effective treatments. Drug treatment may
provide a unique opportunity to educate drug abusers about the risks of HIV infection and transmission. The emergence of
HIV and AIDS may also lead to a resurgence of tuberculosis, especially in prison populations.

What’s Next: The country’s health practitioners and policymakers continue to improve treatment for heroin dependence.
But efforts need to be increased to deal with escalating problems associated with amphetamine-type stimulants.

Publication: Dr. Mahmud Mazlan of the Substance Abuse Center in Muar, Malaysia, and his colleagues published their
findings in the September 2006 issue of Drug and Alcohol Review.

The National Institute on Drug Abuse (NIDA) is a component of the National Institutes of Health, U.S. Department of Health and Human Services. NIDA supports most of the world’s research on the health aspects of drug abuse and addiction. The Institute carries out a large variety of programs to ensure the rapid dissemination of research information and its implementation in policy and practice. Fact sheets on the health effects of drugs of abuse and other topics are available in English and Spanish.

These fact sheets and further information on NIDA research and other activities can be found on the NIDA home page at www.drugabuse.

View drug information on Naltrexone Hydrochloride Tablets. Continue reading

9 In 10 Iowa Voters Support More Government Oversight Of Food

Ninety percent of voting Iowans believe the government should be given additional authority to ensure the food they eat does not make them sick, according to a new poll commissioned by The Pew Charitable Trusts and conducted by Hart Research and Public Opinion Strategies.

Support for stronger food protections is high regardless of voters’ gender, income level or political affiliation. The statewide survey of 511 registered voters, conducted between August 10-12, 2009, has a margin of error of +/- 4.3 percent. Full survey results are available at MakeOurFoodSafe.

The overall support for new safety measures follows high-profile outbreaks in recent years in which pathogens in peanut butter, pistachios, peppers, spinach and other food resulted in illnesses in people across the country – including deaths of a number of children and elderly citizens. According to the Centers for Disease Control and Prevention, an estimated 76 million food-related illnesses occur annually in the United States, with 325,000 people hospitalized and 5,000 dying as a result.

The survey shows that about half (49 percent) of Iowa voters say what they have seen and heard in the last year has made them less confident in the safety of food sold in the United States. In addition, more than half (55 percent) of all seniors have a decrease in confidence.

“Most foodborne illnesses that result in hospitalizations and death are preventable. Despite that, one American every two hours, every day of the year perishes as a result of pathogens in the food they eat,” says Shelley A. Hearne, managing director of the Pew Health Group. “The Food and Drug Administration, which is responsible for the safety of over 80 percent of the foods we eat, does not have the tools or resources it needs to sufficiently protect the public from dangers in the food supply.”

A total of 81 percent of Iowa voters interviewed believe the federal government should be responsible for ensuring that food is safe to eat, and more than half (53 percent) believe the federal government is doing too little to ensure that imported food is safe from contamination. The FDA inspects about one percent of the imported products it regulates, according to agency officials.

Release of the survey comes as the Senate is expected to consider food safety legislation that gives the Food and Drug Administration new oversight and enforcement powers. The House passed its version of the bill in July, which includes stronger inspection authorities for federal officials when investigating domestic facilities and imports.

“Iowans are very clear: the government needs to do more to ensure that our family members won’t get sick from the food on their dinner plates,” says Hearne. “The take-away message from this it is that the public gets it: our antiquated food safety laws greatly need updating so that Americans can have more confidence in the food supply.”

Based on research and critical analysis, the Pew Health Group seeks to improve the health and well-being of all Americans. It advocates policies that reduce potentially dangerous health risks in consumer, medical and food products and services.

Source:
Colin Finan

Pew Health Group Continue reading

Immune Deficiency Linked To Increased Risk Of Infection-Related Cancers

Immune deficiency rather than other risk factors for cancer such as lifestyle are probably
responsible for the increased risk of cancer in immune suppressed populations concludes an
Article in this week’s issue of The Lancet.

Andrew Grulich (University of New South Wales,
Australia) and colleagues did a meta-analysis of cancer incidence in published population-
based studies of people with HIV/AIDS and organ transplant recipients. The authors found
that an extensive range of cancers occurs at increased incidence both in people with HIV/AIDS
and in transplant recipients.

The authors conclude: “The increased rates of cancers we have
found at a very large range of sites suggests a broader than previously appreciated role for
the immune system in the prevention of cancers related to infection.”

thelancet Continue reading

AP/Houston Chronicle Examines HIV Outbreak Among 72 Children, 16 Mothers In Kyrgyzstan

An HIV outbreak among 72 children and 16 mothers at two hospitals in Kyrgyzstan has led to charges of negligence against 14 medical workers, who are believed to have accidentally infected the children through tainted blood and used needles, the AP/Houston Chronicle reports (Saralayeva, AP/Houston Chronicle, 4/9).

Four Kyrgyz physicians were fired in July 2007 for accidentally infecting 10 children and one adult with HIV. Ministry of Health officials said the children and the adult contracted HIV while receiving injections and blood transfusions but gave no other details (Kaiser Daily HIV/AIDS Report, 8/1/07). Hundreds of children have been tested since the outbreak was first discovered in July. Health Minister Marat Mambetov on Tuesday said the infections have been contained.

According to the AP/Chronicle, some of the mothers contracted the virus through breastfeeding their children. HIV/AIDS experts said that although HIV transmission from infants to mothers during breastfeeding is rare, it is possible when the infant has mouth sores and the woman has lesions on her breasts.

The HIV-positive children are receiving antiretroviral drugs at no cost through the government, but their mothers are not eligible for no-cost antiretrovirals if they are in the early stages of the disease, Erkin Bakiyev, director of the country’s national AIDS center, said. The children also are receiving monthly payments of $23 from the government.

The nongovernmental organization Rainbow has begun to provide no-cost legal assistance to some of the HIV-positive women to help them obtain medication and other support services. Fatima Khabibullina, a lawyer at Rainbow, said that some of the women’s husbands have left them since learning of their HIV-positive status. Rainbow Director Fatima Koshokova said, “These women are having huge financial difficulties,” adding, “They should be getting nutritious food, but they are not able to get jobs or to provide decent food for themselves or their children” (AP/Houston Chronicle, 4/9).

Reprinted with kind permission from kaisernetwork. You can view the entire Kaiser Daily Health Policy Report, search the archives, or sign up for email delivery at kaisernetwork/dailyreports/healthpolicy. The Kaiser Daily Health Policy Report is published for kaisernetwork, a free service of The Henry J. Kaiser Family Foundation© 2005 Advisory Board Company and Kaiser Family Foundation. All rights reserved. Continue reading

New Jersey Senator Proposes Plan To Avert HIV/AIDS Drug Copayments

New Jersey state Sen. Joseph Vitale (D) — chair of the Senate Health, Human Services and Senior Citizens Committee — earlier this week proposed a plan to temporarily reduce rebate checks to senior citizens earning $100,000 to $150,000 in an effort to alleviate the effects of possible budget cuts on certain populations, the Newark Star-Ledger reports. Vitale’s proposal also would avert planned $6 to $15 prescription drug copayments for people living with HIV/AIDS in the state (Livio, Newark Star-Ledger, 5/12).

The copayments are part of Gov. Jon Corzine’s (D) $29.8 billion spending proposal for the state’s new fiscal year and would collect $1.36 million by creating copayments for HIV/AIDS drugs based on a sliding scale determined by income. The copayments would affect 9,000 people living with HIV/AIDS who have obtained no-cost medicine from the state because they do not qualify for other assistance programs. Advocates said that the copayments will hurt patients who are already struggling because of the poor economy (Kaiser Daily HIV/AIDS Report, 4/23).

According to the Star-Ledger, Vitale’s proposal would save the state $15.7 million, including $9.7 million needed to allow 17,000 low-income families to enroll in the state’s health insurance program, FamilyCare. Senate Budget Committee Chair Barbara Buono (D) said that she does not believe it is possible to restore program cuts “given the collapse of revenues.” According to the Office of Legislative Services, the current deficit for this year’s budget, which ends June 30, is at least $1.2 billon. Vitale said, “Our convictions are going to be tested as we come to terms with the fact that we simply don’t have enough money to fund all of the state’s priorities.” He added, “But unless funding is restored for programs like NJ FamilyCare, Medicaid drug benefits and the AIDS Drug Distribution Program, I will be voting against the” fiscal year 2010 budget (Newark Star-Ledger, 5/12).

Reprinted with kind permission from kaisernetwork. You can view the entire Kaiser Daily Health Policy Report, search the archives, or sign up for email delivery at kaisernetwork/dailyreports/healthpolicy. The Kaiser Daily Health Policy Report is published for kaisernetwork, a free service of The Henry J. Kaiser Family Foundation.

© 2009 Advisory Board Company and Kaiser Family Foundation. All rights reserved. Continue reading

House Democrats Send Letter To Homeland Security Secretary Chertoff Objecting To New Rules For HIV-Positive People Visiting U.S.

Thirty House Democrats on Monday sent a letter to Homeland Security Secretary Michael Chertoff objecting to new regulations for HIV-positive people visiting the U.S., the AP/Google reports. The lawmakers, along with gay rights groups, say the proposed rules might end up creating more barriers for HIV-positive visitors to the U.S. (Werner, AP/Google, 12/11). President Bush in December 2006 requested the waiver process that enables HIV-positive people to visit the U.S. be streamlined with new administrative rules. The new rules, proposed by the Department of Homeland Security, would remove a requirement that applications for a waiver be reviewed by the U.S. Citizenship and Immigration Services and instead would leave waiver decisions to U.S. consular offices worldwide.

According to some critics, the new rules would require that HIV-positive visitors prove they are bringing with them to the U.S. an “adequate supply of antiretroviral medicines.” Veronica Nur Valdes, a DHS spokesperson, said the current waiver rules already require that HIV-positive visitors “must be traveling with an adequate supply of drugs.” Applicants for a waiver also would have to agree to not extend their visit to the country, and visits would be limited to two 30-day stays annually, according to Victoria Neilson, legal director for Immigration Equality. HIV-positive people who are found to be violating the rules could be permanently banned from entering the U.S. (Kaiser Daily HIV/AIDS Report, 12/6).

According to a White House fact sheet about the new regulations, the “administration is working to end discrimination against people living with HIV/AIDS.” It adds that under the new regulations, a “categorical waiver” will “enable HIV-positive people to enter the [U.S.] for short visits through a streamlined process.” However, applicants seeking a waiver under the new rules will “still have to somehow persuade an official that they are of minimal danger, will not transmit the virus and will not cost the government money,” the letter — which was released on Monday by Rep. Barbara Lee (D-Calif.) — said. It added, “There would be no appeal process. Selecting this pathway would also require applicants to waive any right to readjust their status once in the [U.S.] — a waiver not required under current policy.”

Valdes said the new rules do provide a streamlined process for HIV-positive people to visit the U.S. Valdes did not comment on the letter but said the department will review it and respond. A public comment period on the new rules expired Thursday, but Valdes could not say when a final rule will be published, the AP/Google reports.

According to the Department of State, 139 people were found ineligible to travel to the U.S. on a nonimmigrant visa because of having a communicable disease in fiscal year 2006. It added that 127 of these applicants challenged the finding and were able to obtain a visa, the AP/Google reports. Because these numbers apply to all communicable diseases and not just HIV/AIDS, the state department cannot provide a figure for only HIV/AIDS cases. The numbers also do not take into account people who were discouraged from applying for a visa because of their HIV-positive status or who did not report their status, according to the AP/Google (AP/Google, 12/11).

The letter is available online.

Reprinted with kind permission from kaisernetwork. You can view the entire Kaiser Daily Health Policy Report, search the archives, or sign up for email delivery at kaisernetwork/dailyreports/healthpolicy. The Kaiser Daily Health Policy Report is published for kaisernetwork, a free service of The Henry J. Kaiser Family Foundation. © 2005 Advisory Board Company and Kaiser Family Foundation. All rights reserved. Continue reading

Cells Protected Against HIV Infection By Engineered Protein-Like Molecule

With the help of the human immunodeficiency virus (HIV) and molecular engineering, researchers have designed synthetic protein-like mimics convincing enough to interrupt unwanted biological conversations between cells.

Interactions between proteins are fundamental to many biological processes, including some less-than-desirable ones like infections and tumor growth. For example, HIV and several other human viruses – including influenza, Ebola and the severe acute respiratory syndrome (SARS) virus – rely on interactions both among their own proteins and with host cell proteins to infect the cells.

“There’s a lot of information transfer that occurs when proteins come together, and one would often like to block that information flow,” says Samuel Gellman, a chemistry professor at the University of Wisconsin-Madison.

In a fundamental study of how to control protein shape, Gellman’s UW-Madison research team, including former postdoctoral fellow W. Seth Horne, now at the University of Pittsburgh, and graduate student Lisa Johnson, created a set of peptide-like molecules that successfully blocked HIV infection of human cells in laboratory experiments.

By interacting with a piece of a crucial HIV protein called gp41, the synthetic molecules physically prevent the virus from infecting host cells.

The idea shows promise as a new avenue for targeting other unwanted protein interactions as well, Gellman says. The work, performed with a group led by John Moore and Min Lu at the Weill Medical College of Cornell University, is described in a paper appearing online this week (Aug. 17) in the Proceedings of the National Academy of Sciences.

Past attempts to prevent infection by selectively interfering with these interactions have had limited success, he says. Most drugs are small molecules and are not very effective at blocking most protein-protein interactions, which involve large molecular surfaces. Short snippets of proteins, or peptides, can be more effective than small molecules but are easily broken down by enzymes in the body and so require large and frequent doses that are difficult for patients to manage.

The new synthetic approach avoids these pitfalls by creating peptide-like molecules with a modified structure that degrading enzymes have trouble recognizing.

“We want to find an alternate language, an alternate way to express the information that the proteins express so that we can interfere with a conversation that one protein is having with another,” Gellman explains.

Like engineers adjusting molecular blueprints, Gellman and his colleagues made structural tweaks to the backbones of their synthetic molecules to improve stability while retaining the three-dimensional shape necessary to recognize and interact with the HIV gp41 protein. The resulting molecules – dubbed “foldamers” – are hybrids of natural and unnatural amino acid building blocks, a combination that allows the scientists to control shape, structure and stability with much greater precision than is currently possible with natural amino acids alone.

In addition to adopting a shape that can interrupt the protein-protein dialogue, the novel foldamer has the additional advantage of being highly resistant to degradation by naturally occurring enzymes, which are stymied by the foldamer’s unusual structure. This means the molecule can remain effective for a longer time and at lower doses.

Several of the synthetic foldamers showed potent antiviral activity against HIV when applied to cultured human cell lines in a dish. Although it is not clear that the foldamers themselves could ever be used as anti-HIV drugs, Gellman emphasizes, the results show that this type of approach has great potential to lead to new ways to think about designing molecules for antiviral therapies and other biomedical applications.

“You don’t have to limit yourself to the building blocks that nature uses,” Gellman says. “There’s a huge potential here because the strategy we use is different from what the pharmaceutical and biotech industries now employ.”

The study was supported by grants from the National Institutes of Health.

Source:
Sam Gellman

University of Wisconsin-Madison Continue reading

Libya’s Judicial Council Commutes Death Sentence For Medical Workers In HIV Infection Case

Libya’s Supreme Judicial Council on Tuesday commuted the death sentences of six medical workers who were sentenced for allegedly intentionally infecting hundreds of Libyan children with HIV, the New York Times reports (Smith, New York Times, 7/18).

The five Bulgarian nurses and one Palestinian doctor in May 2004 were sentenced to death by firing squad for allegedly infecting 426 children with HIV through contaminated blood products at Al Fateh Children’s Hospital in Benghazi, Libya. They also were ordered to pay a total of $1 million to the families of the HIV-positive children. The Libyan Supreme Court in December 2005 overturned the medical workers’ convictions and ordered a retrial in a lower court. A court in Tripoli, Libya, in December 2006 convicted the health workers and sentenced them to death. The medical workers then filed an appeal of the December 2006 conviction with the Libyan Supreme Court. The Supreme Court upheld the conviction earlier this month.

The Gaddafi Development Foundation — which is headed by Libyan leader Muammar Gaddafi’s son, Seif al-Islam Gaddafi — confirmed on Sunday that the families of the children accepted a compensation package of about $460 million (Kaiser Daily HIV/AIDS Report, 7/17).

The judicial council — which can approve or cancel the Supreme Court’s conviction of the medical workers or issue a less serious sentence — reduced the sentence to life in prison after each family received the compensation package, the Los Angeles Times reports. Idriss Lagha, head of the Association for the Families of HIV-Infected Children, on Tuesday confirmed that each family had received the payment. According to Lagha, the families’ acceptance of the compensation implies that they have abandoned their complaint against the medical workers and their call for the workers’ execution.

Lagha indicated that the money was being transferred through an international fund supported by several countries — including Bulgaria and other Balkan nations — the European Union and the U.S. The fund allows countries to provide money without directly paying the families, according to the Los Angeles Times (Wilkinson, Los Angeles Times, 7/18). However, it remains unclear “where the money paid to the families came from,” the New York Times reports. Seif al-Islam Gaddafi has indicated that Bulgaria, Croatia, the Czech Republic and Slovakia forgave some of Libya’s debt, freeing funds that were part of the compensation package. But the governments of those countries have denied the claim, according to the New York Times. Bulgaria has committed to participate in the international fund (New York Times, 7/18).

Reaction
The commutation of the sentence could “pave the way” for an agreement to extradite the medical workers to Bulgaria, where they likely will be released, the New York Times reports (New York Times, 7/18). Bulgarian Foreign Minister Ivailo Kalfin during a news conference in Sofia, Bulgaria, said, “For us, the case will be over after the Bulgarian women come home,” adding, “We are ready to start work on the transfer immediately” (Los Angeles Times, 7/18). According to Dimiter Tzantcev, a Foreign Ministry spokesperson, Bulgarian institutions already have “started the procedural steps needed for the transfer,” and the “formal request” will be made on Thursday.

Libya Foreign Minister Abdel-Rahman Shalqam said his government most likely will grant the request, but he did not give a date. “Issuing this decision automatically closes the legal case against them,” Shalqam said, adding, “There is a legal cooperation agreement between Libya and Bulgaria, and we don’t mind that the Bulgarian nurses and the Palestinian doctor benefit from it” (New York Times, 7/18). Department of State spokesperson Sean McCormack said the U.S. is “encouraged” by the council’s decision, adding, “We urge the Libyan government to now find a way to allow the medics to return home” (Sullivan, Washington Post, 7/18). “The fact that (Libya’s) High Judicial Council did not uphold the death sentence is a first relief,” European Commission President Jose Manuel Barroso and E.U. External Relations Commissioner Benita Ferrero-Waldner said in a joint statement. They added, “However, our objective is a solution which allows for the departure of the Bulgarian and Palestinian medical personnel from Libya and their transfer to the E.U. as soon as possible” (El-Deeb, AP/ABC News, 7/18).

“Reprinted with permission from kaisernetwork. You can view the entire Kaiser Daily Health Policy Report, search the archives, or sign up for email delivery at kaisernetwork/dailyreports/healthpolicy. The Kaiser Daily Health Policy Report is published for kaisernetwork, a free service of The Henry J. Kaiser Family Foundation . © 2005 Advisory Board Company and Kaiser Family Foundation. All rights reserved. Continue reading

Hundreds Of Thousands Of Viral Species Present In The World’s Oceans

The ocean is full of life–large, small, and microscopic. Bacteriophage (phage) viruses are minute, self-replicating bundles that alter microorganisms’ genetic material and moderate their communities through predation and parasitism. Despite their small size, they are astoundingly abundant with about as many of them in a bucket full of seawater as there are humans on the planet. As a result, they can have a huge impact ecologically.

In a new study published online this week in the open access journal PLoS Biology, Florent Angly, Forest Rohwer, and colleagues detail their metagenomic study of the diversity of bacteriophage present in water samples collected from 68 sites over 10 years from four oceanic regions (the Sargasso Sea, the Gulf of Mexico, British Columbia coastal waters, and the Arctic Ocean). They use pyrosequencing (a technique that enables collection of many DNA sequence reads for less cost than conventional sequencing) to large samples, rather than individual organisms to gain insights into diversity, geography, taxonomy, and ecosystem functioning. This approach identified tremendous viral diversity with greater than 91% of DNA sequences not present in existing databases.

Angly and colleagues analyzed the distribution of marine phages among the sampling sites and found a correlation between geographic distance and genetic distance of viral species, supporting the idea that the marine virome varies from region to region. They also investigated how similar the viromes from each location were–in fact, the differences were mostly explained by variations in relative abundance of the viral species, and supports the notion that although everything is everywhere, the environment selects.

Overall, they saw that samples from the British Columbia coast were the most genetically diverse (consistent with its nutrient-rich environment). The other three samples showed increasing diversity with decreasing latitude, a trend that parallels previous findings from terrestrial ecosystems. In fact, the researchers predict that the world’s oceans hold a few hundred thousand broadly distributed viral species, with some species-rich regions likely harboring the majority of these species.

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Citation: Angly F, Felts B, Breitbart M, Salamon P, Edwards R, et al. (2006) The marine viromes of four oceanic regions. PLoS Biol 4(11): e368. DOI: 10.1371/journal.pbio. 0040368.

CONTACT:

Forest Rohwer
San Diego State University
5500 Campanile Dr.
San Diego, CA 92182

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All works published in PLoS Biology are open access. Everything is immediately available–to read, download, redistribute, include in databases, and otherwise use–without cost to anyone, anywhere, subject only to the condition that the original authorship and source are properly attributed. Copyright is retained by the authors. The Public Library of Science uses the Creative Commons Attribution License.

Contact: Natalie Bouaravong

Public Library of Science Continue reading