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Vol. XII, No. 19 ~ EINet News Briefs ~ Sep 18, 2009
*****A free service of the APEC Emerging Infections Network*****
APEC EINet News Briefs offers the latest news, journal articles, and notifications for emerging infections affecting the APEC member economies. It was created to foster transparency, communication, and collaboration in emerging infectious diseases among health professionals, international business and commerce leaders, and policy makers in the Asia-Pacific region.
In this edition:
1. Influenza News
- Cumulative number of human cases of avian influenza A/(H5N1)
- Global: WHO update on pandemic influenza H1N1
- Global: Influenza H1N1 contagious longer than thought
- Global: Study on respirators versus masks hailed as landmark
- Global: Swine flu death rate similar to seasonal flu
- Spain: Influenza H1N1 Intensive Care Patients
- Indonesia: avian influenza A/(H5N1) infects hundreds of thousands of chickens
- Canada: Second drug-resistant case of pandemic influenza H1N1
- USA: Update on pediatric influenza H1N1 cases
- USA: FDA approved Influenza A (H1N1) 2009 monovalent vaccines
- USA: Flu cases up 21% on US college campuses
2. Infectious Disease News
- Viet Nam: 3000 recorded cases of fascioliasis infection so far in 2009
- Indonesia: Suspected Rabies Death
- Australia: Eight people monitored for Hendra virus infection
- USA (Maine): Three family members bit by rabid kitten
- USA (Wisconsin): New tick-borne infection gaining foothold in region
- USA (New Hampshire): 3-year old infected with Eastern Equine Encephalitis virus
- USA (Massachusetts): 3 Students with symptoms of mumps virus infection
- INFLUENZA A/H1N1
- AVIAN INFLUENZA
- CHOLERA, DIARRHEA, & DYSENTARY
- Clinical and Laboratory Features of Human Plasmodium knowlesi Infection
- Intensive care adult patients with severe respiratory failure caused by Influenza A (H1N1)v in Spain
- The Impact of the Demographic Transition on Dengue in Thailand: Insights from a Statistical Analysis and Mathematical Modeling
- Stockpile of personal protective equipment in hospital settings: Preparedness for influenza pandemics
- Conference: World Response Conference on Global Outbreak 2009: H1N1 Flu + H5N1 Flu
- Updated guidance and information from the US CDC
1. Influenza News
Cumulative number of human cases of avian influenza A/(H5N1)
Economy / Cases (Deaths)
China/ 7 (4)
Egypt/ 34 (4)
Viet Nam/ 4 (4)
Total/ 45 (12)
***For data on human cases of avian influenza prior to 2009, go to: http://depts.washington.edu/einet/humanh5n1.html
Total no. of confirmed human cases of avian influenza A/(H5N1), Dec 2003 to present: 440 (262).
Avian influenza age distribution data from WHO/WPRO: http://www.wpro.who.int/sites/csr/data/data_Graphs.htm
WHO's maps showing world's areas affected by H5N1 avian influenza (last updated 5/10/09): http://gamapserver.who.int/mapLibrary/
WHO’s timeline of important H5N1-related events (last updated 7/29/09): http://www.who.int/csr/disease/avian_influenza/ai_timeline/en/index.html
Global: WHO update on pandemic influenza H1N1
Active transmission persists in tropical regions of the Americas and Asia. Many countries in Central America and the Caribbean continue to report declining activity for the second week in a row. However, countries in the tropical region of South America (represented by countries such as Bolivia, Ecuador, and Venezuela) are reporting increasing levels of respiratory disease. In the tropical regions of Asia, respiratory disease activity remains geographically regional or widespread but the trend is generally increasing as noted in India, Bangladesh, and Cambodia.
In the temperate regions of the Northern Hemisphere activity is variable. In the United States, regional increases in influenza activity are being reported, most notably in the south-eastern states. Most of Europe is reporting low or moderate respiratory diseases activity, but parts of Eastern Europe are beginning to report increases in activity.
WHO Collaborating Centers and other laboratories continue to report sporadic isolates of oseltamivir-resistant influenza virus. Twenty-one such virus isolates have now been described from around the world, all of which carry the same H275Y mutation that confers resistance to the antiviral oseltamivir but not to the antiviral zanamivir.
Pandemic (H1N1) 2009 influenza virus continues to be the predominant circulating virus of influenza, both in the northern and southern hemisphere.
Global: Influenza H1N1 contagious longer than thought
Three reports suggest this is so. De Serres and other researchers in Canada took nose and throat swabs from 43 patients with lab-confirmed flu and dozens of other sick family members. On the eighth day after symptoms 1st appeared, 19 to 75 percent showed signs of virus remaining in their noses, depending on the type of test used. "This proportion appears to be very big, and it is," but it's not clear how much virus is needed to actually spread flu, so the lower number is more reliable, he said.
Dr. David C. Lye reported on 70 patients treated at Tan Tock Seng Hospital in Singapore. Using a very sensitive test to detect virus in the nose or throat, he found that 80 percent had it 5 days after symptoms began, and 40 percent 7 days after. Some still harbored virus as long as 16 days later. How soon they started on antiviral medicines such as Tamiflu made a difference in how much virus was found, but not whether virus was present at all.
A third report came from Dr. Guillermo Ruiz-Palacios of the National Institutes of Medical Science and Nutrition in Mexico, where the first cases of swine flu were detected. Infected people "shed the virus for a very, very long time," often for more than a week after the start of symptoms, he told the conference. This was especially true of obese people, and patients who started on medicines longer than 2 days after symptoms first appeared.
Global: Study on respirators versus masks hailed as landmark
The study, which involved close to 2,000 hospital staffers in Beijing, showed that N95 respirators reduced the risk of respiratory illness by a significant 60% and the risk of confirmed influenza by 75%, whereas surgical masks had no effect.
The study was reported at an American Society for Microbiology meeting in San Francisco this week but has not yet been published in full form. It is described as the first randomized controlled trial comparing the effectiveness of N95 respirators and surgical masks.
N95 respirators are designed to fit closely to the face and filter out 95% of airborne particles, whereas surgical masks are looser fitting and were originally designed to prevent the wearer from infecting others. But health workers say the tight-fitting N95s are uncomfortable and difficult to wear for long periods, and hospitals sometimes have trouble keeping them in supply. Surgical masks are more comfortable and cheaper, but scientists have not found much evidence that they protect wearers from respiratory pathogens.
In the face of the H1N1 flu pandemic, respiratory protection for health workers has been a big issue. Two weeks ago, the National Academy of Sciences' Institute of Medicine (IOM) issued a report affirming the current Centers for Disease Control and Prevention (CDC) guidance on the topic. The CDC recommends use of N95s by all healthcare workers who enter the rooms of patients with confirmed or suspected H1N1 infection. The same advice goes for emergency medical personnel who come in close contact with such patients.
The researchers recruited 1,936 front-line workers at 24 Beijing hospitals, according to the study abstract from the Interscience Conference on Antimicrobials and Chemotherapy (ICAAC). They were assigned to one of four groups: surgical masks, fit-tested N95s, non-fit-tested N95s, or control (no respiratory protection). The volunteers wore their assigned form of protection for 4 weeks and were monitored for illness for 5 weeks.
The authors found that surgical masks had no protective effect. In contrast, the N95s, compared with the controls, were linked with a 60% reduction in risk for any respiratory illness, a 75% reduction in flu-like illness, a 56% decrease in lab-confirmed respiratory illness, and a 75% reduction in confirmed flu, according to the report. The reductions met the test of statistical significance. However, the researchers found that fit-testing of the N95s—recommended by manufacturers to keep air from leaking around them—made no difference in protection.
"These data are the first clinical data to confirm the superiority of N95 masks in preventing respiratory infections," the authors state. "Front line health workers are key to an effective pandemic response, and should be protected with N95 masks."
As for the finding that fit-testing made no difference in benefits from the N95s, Lisa Brosseau, a University of Minnesota researcher who has studied respiratory protection for years, suggested a possible explanation. She said MacIntyre told the IOM committee at the August workshop that her team used an N95 specially designed by 3M Co. for the Chinese face and that fewer than 5% of volunteers failed to pass the fit test. "Thus, this is a mask that is likely to fit most adults in the Chinese population very well, which is why fit testing did not make a significant difference in the rates of disease," Brosseau said.
MacIntyre C, Wang Q, Cauchemez S, et al. The first randomized, controlled clinical trial of surgical masks compared to fit-tested and non-fit-tested N95 masks in prevention of respiratory virus infection in hospital health care workers in Beijing, China. Presented Sep 15, 2009, at ICAAC meeting, San Francisco.
Global: Swine flu death rate similar to seasonal flu
Lipsitch took information from around the world on how many people had reported they had influenza-like illness, which may or may not actually be influenza; government reports of actual hospitalizations and confirmed deaths. He came up with a range of mortality from swine flu, from 0.007 percent to 0.045 percent. Either way, having new information about how many people were infected and did not become severely ill or die makes the pandemic look very mild, he said.
H1N1 swine flu was declared a pandemic in June after flashing around the world in six weeks. Experts all said a true death rate would not be clear for weeks because it is impossible to test every patient and because people with mild cases may never be diagnosed. This lack of information made the epidemics in various countries and cities look worse at first than they actually were, Lipsitch said. People sick enough to be hospitalized are almost always tested first.
Seasonal flu is usually far worse among the elderly, who make up 90 percent of the deaths every year. In contrast, this flu is attacking younger adults and older children, but they are not dying of it at the same rate as the elderly, Lipsitch said.
Spain: Influenza H1N1 Intensive Care Patients
About half of people admitted to ICU [intensive care units] in hospitals for severe complications of influenza A [i.e. pandemic A (H1N1) 2009 virus] had no risk factor or disease, according to a study conducted in 21 Spanish hospitals. The study, presented on the website of the medical journal Critical Care is the largest ever conducted in Europe on influenza cases requiring intensive care. Their findings contradict one of the messages on influenza A released by the Ministry of Health and the Department of Health, which have repeatedly reported that patients with influenza A cases had previous health problems.
The findings contain important messages for both the general population and for health authorities and medical intensivists. For the general population, there is an appeal to healthy people without risk factors to avoid falling prey to overconfidence in regard to influenza A. Although the vast majority of those affected will overcome the flu without complications, a small percentage will have pneumonia and should be hospitalized.
"The natural symptoms of the disease are usually 3 or 4 days of fever, generally over 38 C with a steady improvement in the following days. But a minority of patients, around the 4th or 5th day, get worse," reports Jordi Rello, head of the intensive care unit of Tarragona Joan XXIII Hospital and coordinator of the study. Therefore, if a sufferer experiences breathing difficulties after contracting the flu, they should seek medical attention urgently, but the main point of the study is that no risk factors or diseases have made them particularly vulnerable.
Looking to health authorities, the study indicates that efforts to contain influenza A should not be limited to prevent disease and to address mild cases in primary care but also to meet serious cases in ICUs. It is estimated that only 0.2 percent of patients suffer serious complications, according to a calculation based on the experience of Britain. This means that for every million affected, 2000 suffer complications, a figure that may overwhelm the capacity of the ICU departments.
The study results confirm that obesity and pregnancy are risk factors for serious complications. The average age of patients in ICU for influenza A is 40 years, of which about 25 percent die.
Indonesia: avian influenza A/(H5N1) infects hundreds of thousands of chickens
Reportedly bird flu H5N1 attacked hundreds of thousands of layer chickens in several farms in Kabupaten Banyumas, Central Java. Infected chickens had received avian influenza vaccination. The massive bird flu attack was distributed evenly in Sumbang, Karanglewes, Kedungbanteng Serat, and Cilongok within weeks. Avian influenza infection did not kill chickens that received vaccination, but it caused suppression of egg production.
Canada: Second drug-resistant case of pandemic influenza H1N1
Alberta Health Services is reporting Canada's second drug-resistant case of swine flu [pandemic (H1N1) 2009] virus infection, one of about 24 such cases around the world. Officials were busy 15 Sep 2009 trying to determine if anyone who came into contact with the Alberta woman last month [August 2009] has been infected, but they were optimistic that this was an isolated case. "The patient was not hospitalized and has since recovered," said Dr. Gerry Predy, Alberta's senior medical officer of health. "This is not unexpected. However, it is important because oseltamivir is one of our main tools in dealing with the pandemic. But we don't think this is going to change our approach in any way because it is an isolated case as far as we know at this time."
Health officials say any resistance to oseltamivir, also known as Tamiflu, could possibly lead to further cases of resistant disease and might affect how the disease spreads. Information about the Alberta case has been forwarded to the federal government and the World Health Organization. Predy said officials haven't determined if any people who were in contact with the woman had taken antiviral medication. Officials were not sure if she developed an infection with the resistant strain from the outset or developed the resistance during treatment.
Other resistant cases have been reported in the United States, Denmark, Australia, China and Singapore [and Japan, see comment below]. Most of the cases have been in people who have taken the drug, either as treatment for swine flu or to prevent swine flu after they were exposed to it.
People who are resistant to Tamiflu may also be treated with the antiviral drug zanamivir. Predy said the drug-resistant case will not affect Alberta's plan to roll out a swine flu vaccination program this fall, probably in November 2009. "This is nothing that should cause any kind of concern," Predy said. "It is something that means we will just have to keep the monitoring process in place."
USA: Update on pediatric influenza H1N1 cases
USA: FDA approved Influenza A (H1N1) 2009 monovalent vaccines
USA: Flu cases up 21% on US college campuses
2. Infectious Disease News
Viet Nam: 3000 recorded cases of fascioliasis infection so far in 2009
Fascioliasis, a disease caused by an infestation of parasitic liver flukes, is affecting more people in the central and central highlands regions, with some 3000 cases recorded in 2009, according to the health ministry's Institute of Mariology, Parasitology and Entomology in Quy Nhon. Trieu Nguyen Trung, the institute's director general, said the latest figure was 45 percent more than the number over the same period in 2008.
Fascioliasis is spread by cattle that are allowed to wander freely in the region and disperse larvae into water environments. Since the local people are in the habit of eating water vegetables and drinking
water without boiling it first, it's easy for them to be infected, Trung explained. It is estimated that 40 to 70 percent of local cattle are infected with the disease, he said.
Indonesia: Suspected Rabies Death
A month after she had been bitten, the victim reported feeling unwell. On Sat 12 Sep 2009 she experienced symptoms such as drastic sweating around her head, chest pains, and difficulty in breathing. She was then taken to Tabanan Hospital and received emergency treatment and 2 types of medication. Afterwards she was told to rest at home. When her condition did not improve she was taken to Sanglah Hospital 13 Sep 2009, where she was placed in an isolation room. It appears that she was already paralyzed and could not be resuscitated, finally dying 14 Sep 2009.
As of 15 Sep 2009, there have been 3 fatal cases of suspect rabies: 2 victims came from Desa Buahan, Tabanan, and 1 from Kediri, Tabanan.
Australia: Eight people monitored for Hendra virus infection
This is the 13th known instance of Hendra virus infection since 1994. A Rockhampton vet died on 1 Sep 2009, after catching the virus from an infected horse he treated at the Cawarral property on 28 Jul 2009.
USA (Maine): Three family members bit by rabid kitten
State health officials say members of a western Maine family who were bitten by a rabid kitten are being treated. The family dog, which was also bitten, is getting a rabies booster. Officials say a stray kitten that was taken in by the Oxford County family in late August 2009 was found to be rabid. The kitten had bitten three family members and their dog. The kitten has been euthanized. The three individuals bitten by the cat will receive treatment over the next 28 days. The dog was current on its rabies vaccination, and will be placed in a 45-day quarantine. So far this year, a total of 42 rabid animals have been identified in Maine. That includes 22 raccoons, 10 skunks, six foxes, 3 bats and one cat.
USA (Wisconsin): New tick-borne infection gaining foothold in region
"It is an emerging infection in this area," said Dean Jobe, researcher and supervisor of Gundersen Lutheran's laboratories. "In collecting ticks, we have found it in 10 to 15 percent of the ticks." Only a few years ago, the disease was rare in the La Crosse area, he said. "It is mimicking early Lyme," Jobe said. "We used to say we couldn't find ticks with Lyme south of I-90, and now we see plenty of ticks, and the same is happening with anaplasmosis." Unlike Lyme, anaplasmosis is an infection of the white blood cells, he said. Lyme disease is primarily a skin infection that gets into the bloodstream and spreads into the joints, Jobe said.
Kowalski said anaplasmosis is treated the same way as Lyme, with a tetracycline antibiotic. "What's rewarding is when patients are put on antibiotics, within 24 to 36 hours they feel a lot better," he said. He also said prevention measures and the tick season from early spring to late fall are the same for both diseases. Kowalski said the same person can get the two infections at the same time. He said most La Crosse area primary care, urgent care and emergency medicine physicians are aware of anaplasmosis.
Jobe said the number of Lyme cases has continued to rise every year due to a bigger deer population and mild winters. "We have a huge deer population that supports ticks, and I think anaplasmosis has established itself in the area," Jobe said. "It's a little too early to say if anaplasmosis will be as common as Lyme, but there is a growing concern it could become problematic," he said.
USA (New Hampshire): 3-year old infected with Eastern Equine Encephalitis virus
Candia is taking a new look at plans to control the disease. The reviews of options started as a regular public meeting and ended with selectmen deciding unanimously to start spraying certain areas to kill mosquitoes, a swift sign of the seriousness of this year's  EEE season. The father of this year's only EEE [virus] victim took to the floor at the meeting where he echoed other requests that Candia take another look at how it controls mosquitoes.
State officials said they aren't sure what led to the sudden increase in incidents of the disease, but the wet summer might have helped mosquito populations grow.
USA (Massachusetts): 3 Students with symptoms of mumps virus infection
The following websites provide the most current information, surveillance, and guidance.
- WHO regional offices
- North America
- Other useful sources
In an accompanying commentary, Cameron Simmons and Jeremy Farrar (uninvolved in the research) from the Oxford University Clinical Research Unit in Ho Chi Minh City, Viet Nam discuss the changing patterns of dengue epidemiology and the implications for clinical management and vaccines. Because the clinical management of dengue in children differs from that of adults, the increase in the number of adults in the case mix of dengue patients presents new challenges for clinicians. As a result, Simmons and Farrar argue that it must be a priority to build upon Cummings and colleagues' work in Thailand and to "understand if other dengue-endemic countries in Southeast Asia and Central and South America are experiencing similar temporal associations between demography and dengue epidemiology, and if so, why."
Between 30 Aug and 5 Sep , the nation recorded another 410 new dengue cases, which brings the number of Malaysians infected with the disease to 30 110 up to 5 Sep 2009. During the same period last year (1 Jan-5 Sep 2008) there were 30 956 cases and 71 deaths.
Director-general of Health Tan Sri Dr Ismail Merican said 22 dengue hot spots were identified last week, with many of the spots located in Selangor, Johor, Perak, Sarawak, and Kuala Lumpur.
Dr Le Minh Thuan, director of the Dam Doi- Ca Mau Medical Center in the southern province of Ca Mau, said in the last 8 months [January-August 2009], hospitals and health centers have treated nearly 450 cases of whom 122 were seriously affected.
CHOLERA, DIARRHEA, & DYSENTARY
Eigil Sorensen, WHO's representative in Papua New Guinea, said cholera appeared in 2 coastal villages in northern Morobe Province at the end of July 2009 and gradually spread to 4 districts in the province, but was not identified until a month later. "Cholera hasn't been reported in Papua New Guinea for the last 50 years," Sorenson said, adding that the world health body was investigating the cause of the outbreaks. "It's a major concern, mainly because the healthcare system in PNG remains weak. Rural health services are quite weak and if cholera becomes endemic, it will become a major challenge," he said.
Of the 130 reported cases so far, there had been 12 deaths, Sorensen said, and the disease appeared to be spreading through low level transmission. "Since there is low level transmission and the number of cases remains relatively low, we think there is no contamination of any major water sources," he said. However, the disease has appeared in Lae, the provincial capital, which Sorenson attributed to people traveling from rural areas into the city.
Morobe Province has also been hit by unrelated outbreaks of shigellosis, a bacterium that causes bloody diarrhea. Sorenson said about 40 people might have died from shigella in the last month in remote districts in Morobe.
Clinical and Laboratory Features of Human Plasmodium knowlesi Infection
Daneshvar C et al. Clin Infect Dis. 27 July 2009; 49: 852-860. Available at http://www.journals.uchicago.edu/doi/abs/10.1086/605439?cookieSet=1&journalCode=cid.
Background. Plasmodium knowlesi is increasingly recognized as a cause of human malaria in Southeast Asia but there are no detailed prospective clinical studies of naturally acquired infections.
Methods. In a systematic study of the presentation and course of patients with acute P. knowlesi infection, clinical and laboratory data were collected from previously untreated, nonpregnant adults admitted to the hospital with polymerase chain reaction–confirmed acute malaria at Kapit Hospital (Sarawak, Malaysia) from July 2006 through February 2008.
Results. Of 152 patients recruited, 107 (70%) had P. knowlesi infection, 24 (16%) had Plasmodium falciparum infection, and 21 (14%) had Plasmodium vivax. Patients with P. knowlesi infection presented with a nonspecific febrile illness, had a baseline median parasitemia value at hospital admission of 1387 parasites/μL (interquartile range, 6–222,570 parasites/μL), and all were thrombocytopenic at hospital admission or on the following day. Most (93.5%) of the patients with P. knowlesi infection had uncomplicated malaria that responded to chloroquine and primaquine treatment. Based on World Health Organization criteria for falciparum malaria, 7 patients with P. knowlesi infection (6.5%) had severe infections at hospital admission. The most frequent complication was respiratory distress, which was present at hospital admission in 4 patients and developed after admission in an additional 3 patients. P. knowlesi parasitemia at hospital admission was an independent determinant of respiratory distress, as were serum creatinine level, serum bilirubin, and platelet count at admission ( for each). Two patients with knowlesi malaria died, representing a case fatality rate of 1.8% (95% confidence interval, 0.2%–6.6%).
Conclusions. Knowlesi malaria causes a wide spectrum of disease. Most cases are uncomplicated and respond promptly to treatment, but approximately 1 in 10 patients develop potentially fatal complications.
Intensive care adult patients with severe respiratory failure caused by Influenza A (H1N1)v in Spain
Introduction. Patients with influenza A (H1N1)v infection have developed rapidly progressive lower respiratory tract disease resulting in respiratory failure. We describe the clinical and epidemiologic characteristics of the first 32 persons reported to be admitted to the intensive care unit (ICU) due to influenza A (H1N1)v infection in Spain.
Methods. We used medical chart reviews to collect data on ICU adult patients reported in a standardized form. Influenza A (H1N1)v infection was confirmed in specimens using real-time reverse transcriptase-polymerase-chain-reaction (RT PCR) assay.
Results. Illness onset of the 32 patients occurred between June 23 and July 31, 2009. The median age was 36 years (IQR = 31 - 52). Ten (31.2%) were obese, 2 (6.3%) pregnant and 16 (50%) had pre-existing medical complications. Twenty-nine (90.6%) had primary viral pneumonitis, 2 (6.3%) exacerbation of structural respiratory disease and 1 (3.1%) secondary bacterial pneumonia. Twenty-four patients (75.0%) developed multiorgan dysfunction, 7 (21.9%) received renal replacement techniques and 24 (75.0%) required mechanical ventilation. Six patients died within 28 days, with two additional late deaths. Oseltamivir administration delay ranged from 2 to 8 days after illness onset, 31.2% received high-dose (300mg/day), and treatment duration ranged from 5 to 10 days (mean 8.0 + 3.3).
Conclusions. Over a 5-week period, influenza A (H1N1)v infection led to ICU admission in 32 adult patients, with frequently observed severe hypoxemia and a relatively high case-fatality rate. Clinicians should be aware of pulmonary complications of influenza A (H1N1)v infection, particularly in pregnant and young obese but previously healthy persons.
The Impact of the Demographic Transition on Dengue in Thailand: Insights from a Statistical Analysis and Mathematical Modeling
Background. An increase in the average age of dengue hemorrhagic fever (DHF) cases has been reported in Thailand. The cause of this increase is not known. Possible explanations include a reduction in transmission due to declining mosquito populations, declining contact between human and mosquito, and changes in reporting. We propose that a demographic shift toward lower birth and death rates has reduced dengue transmission and lengthened the interval between large epidemics.
Methods and Findings. Using data from each of the 72 provinces of Thailand, we looked for associations between force of infection (a measure of hazard, defined as the rate per capita at which susceptible individuals become infected) and demographic and climactic variables. We estimated the force of infection from the age distribution of cases from 1985 to 2005. We find that the force of infection has declined by 2% each year since a peak in the late 1970s and early 1980s. Contrary to recent findings suggesting that the incidence of DHF has increased in Thailand, we find a small but statistically significant decline in DHF incidence since 1985 in a majority of provinces. The strongest predictor of the change in force of infection and the mean force of infection is the median age of the population. Using mathematical simulations of dengue transmission we show that a reduced birth rate and a shift in the population's age structure can explain the shift in the age distribution of cases, reduction of the force of infection, and increase in the periodicity of multiannual oscillations of DHF incidence in the absence of other changes.
Conclusions. Lower birth and death rates decrease the flow of susceptible individuals into the population and increase the longevity of immune individuals. The increase in the proportion of the population that is immune increases the likelihood that an infectious mosquito will feed on an immune individual, reducing the force of infection. Though the force of infection has decreased by half, we find that the critical vaccination fraction has not changed significantly, declining from an average of 85% to 80%. Clinical guidelines should consider the impact of continued increases in the age of dengue cases in Thailand. Countries in the region lagging behind Thailand in the demographic transition may experience the same increase as their population ages. The impact of demographic changes on the force of infection has been hypothesized for other diseases, but, to our knowledge, this is the first observation of this phenomenon.
Stockpile of personal protective equipment in hospital settings: Preparedness for influenza pandemics
Background. Personal protective equipment (PPE) is known to be a crucial means of preventing influenza pandemics; however, the amount of PPE that should be stored in hospital settings has been unclear.
Objectives. The purpose of this paper is to propose a PPE calculation system to help hospitals to decide their PPE stockpile.
Methods. We searched influenza guidelines from a number of countries and research papers on protective devices and infectious diseases. The PPE calculation system included factors such as the influenza pandemic period, risk classification by health care workers (HCW) type, and the type and number of PPE for a HCW per day.
Results. We concluded that 4 sets of PPE (N95 respirators, double gloves, gowns, and goggles) per day should be prepared for HCWs in a high-risk group. Similarly, 2 sets of appropriate PPE, depending on the risk level, are required for medium- and low-risk groups. In addition, 2 surgical masks are required for every worker and inpatient and 1 for each outpatient. The PPE stockpile should be prepared to cover at least an 8-week pandemic.
Conclusion. Purchasing a PPE stockpile requires a sizable budget. The PPE calculation system in this paper will hopefully support hospitals in deciding their PPE stockpile.
Conference: World Response Conference on Global Outbreak 2009: H1N1 Flu + H5N1 Flu
Las Vegas, Nevada; 12-13 Nov 2009
Our purpose is to create an Ad Hoc multi-sector Crisis Management Consortium during the event, to be studied as a model by communities worldwide. It is the first world event to invite leaders representing every sector of society to model a community process to help prepare, respond, and recover from a localized outbreak, as well as broader pandemic. Additional information at registration available at http://wrcgo.eve-ex.com/.
Updated guidance and information from the US CDC
Updated Interim Recommendations for Obstetric Health Care Providers Related to Use of Antiviral Medications in the Treatment and Prevention of Influenza for the 2009-2010 Season
2009 H1N1 Influenza Vaccine Q & A