Pandemics and Influenza: Swine Flu H1N1 next?

Nurses in 1918 Flu outbreakToday 4/29/2009 the World Health organization upgraded the “pandemic level” to a level 5 out of 6.  This is the last step before officially declaring a pandemic.  Humans have already dealt with several pandemics in the 20th century and what exactly is a pandemic?

Pandemic

The term “pandemic” comes from Greek with PAN meaning “all” and DEMOS meaning “people”. Actually it was the Greek physician Hippocrates first described influenza in 412 BC.   A pandemic is basically a new, infectious disease that spreads between humans on a large scale.  Currently the WHO uses a scale of 1-6 to rank an infectious disease and its ability for causing a pandemic. 

  • Phase Four:  Human to human spread possible
  • Phase Five: Human to human spread of the virus in at least two countries in one region of the globe
  • Phase Six: Global Pandemic with widespread outbreaks

So looking at the previous few days of the H1N1 influenza virus (swine flu) we cannot be surprised that this is moving towards a “pandemic” and it actually appears that we are already at the pandemic point.  There is currently spread between humans, it has infected people in multiple countries in the same geographic region and it has crossed continents.

 

Come back later, please?Famous Previous and Current Pandemics

The Black Deathof Europe, Plague caused by the bacteria Yersenia Pestis started in the 1300’s and killed 20-30 million Europeans over 6 years

First cholera pandemic at the Indian Sub-continent 1816-1826 killed greater than 10 million and many records indicate a higher toll, all caused by a humble bacteria

Spanish Flu was first noted in March of 1918 in Kansas and had spread to all continents by October.  Estimates of 2.5-5% of the total global population was infected and killed 50 million people in six months

Asian Flu in 1957-1958 killed 2 million globally and about 70,000 in the United States alone

HIV  is an active pandemic that has spread from one continent to another, is infectious and its death toll may reach 100 million in Africa alone, by 2025

Smallpox  is a virus that had a death toll of 500 million in the 20th century alone, until it was eradicated, in an amazing global effort, 1n 1979

Clearly, the term pandemic does not mean the end of the world.  Humans have suffered through and still grapple with pandemics, on a daily basis.  Taking proper personal safety measures such as handwashing, using condoms, covering your cough, not sharing needles and disposing of your dirty tissues properly are what help stop disease spread.

Travel Health and Swine Flu

PillsThe H1N1 virus continues to circle the globe and infect new areas thanks to the “person to person” spread.  Clearly, this influenza outbreak will have long-reaching impact on travelers.  A few things that may help travelers make informed decisions:

  • The Center for Disease Control (CDC) has advised all non-essential travel to Mexico be postponed
  • The World Health Organization has not advised closing international borders or suspending trade

The CDC has advised the following persons to use antiviral medication such as Zanamivir (Relenza) or Oseltamivir (Tamiflu):

  • Household close contacts who are at high-risk for complications of influenza (e.g., persons with certain chronic medical conditions, persons 65 or older, children younger than 5 years old, and pregnant women) of a confirmed, probable or suspected case.
  • School children who are at high-risk for complications of influenza (children with certain chronic medical conditions) who had close contact (face-to-face) with a confirmed, probable, or suspected case.
  • Travelers to Mexico who are at high-risk for complications of influenza (e.g., persons with certain chronic medical conditions, persons 65 or older, children younger than 5 years old, and pregnant women. 
  • Health care workers or public health workers who were not using appropriate personal protective equipment during close contact with an ill confirmed, probable, or suspect case of swine influenza A (H1N1) virus infection during the case’s infectious period.

The following persons are instructed to consider using antiviral post-exposure treatment:

  • Any health care worker who is at high-risk for complications of influenza (e.g., persons with certain chronic medical conditions, persons 65 or older, children younger than 5 years old, and pregnant women) who is working in an area of the healthcare facility that contains patients with confirmed swine influenza A (H1N1) cases, or who is caring for patients with any acute febrile respiratory illness.
  • Non-high risk persons who are travelers to Mexico, first responders, or border workers who are working in areas with confirmed cases of swine influenza A (H1N1) virus infection.

air-purifying_respiratorUse of N-95 respirator masks may also decrease flu transmission, although they require proper fitting to ensure adequate face to mask seal.  Simple surgical masks likely offer little protection.  A 2007 statement from the CDC discussed little evidence that using such masks decreased influenza transmission.

One important point is the reserve supply of these anti-viral drugs and availability.  These medications are prescription only and advice should be sought from a physician before use.  Second, the manufacturers of these medicines are releasing stockpiles to help cope with increasing demand and obviously, areas with known outbreaks and those with confirmed infections receive priority.

Google Maps has created a real-time mapping of the virus spread, according to WHO data

CDC Guidelines for use of antivirals for H1N1:

http://www.cdc.gov/swineflu/recommendations.htm

Swine Flu in USA, Mexico and many more? 4/27/09

Swine Flu is gathering more frequent flier miles than I will ever hope too.  By getting a free-ride in the respiratory systems of paying passengers, swine flu (H1N1) has been able to spread to more and more places.  As of April 27th 2009:

  • Mexico- 19 of 32 states in Mexico have clinical cases and 18 confirmed cases as of 4/26/09.  Thus far, there are 68 estimated fatalities
  • USA-  20 cases in America (8 New York, 7 California, 2 Texas, 2 Kansas, 1 Ohio) located in 5 of 50 states.  There have been no known fatalities in America as of 4/26/09.
  • Canada-  Nova Scotia has confirmed 4 cases of H1N1 (Swine flu) and British Columbia has 2 cases

Many other countries such as New Zealand, Spain, France and Israel have suspected cases that are awaiting testing and confirmation of H1N1.  These suspect cases are all in travelers who have returned from Mexico. 

Countries around the world are increasing surveillance at airports to detect ill travelers and some are beginning to quarantine travelersas they get off planes (Hong Kong, Russia, Japan).

Hong Kong and South Korea have advised their citizens to avoid travel to Mexico, while Italy Poland and Venezuela have issued advice to avoid travel to Mexico and USA.  The WHO (World Health Organization) has made no specific advise to avoid travel plans or stop trade/business.  There is rumor of a US State Department Warning  advising all non-essential travel to Mexico be posponed.  This warning has not yet been issued and is likely set for release on Monday 4/27/09.

The reported cases in New York and Canada are encouraging in the fact that none of the infected have died, but merely suffered a “bout of the flu” and are appearing to recover without problems.  Any person know to have traveled to an area with confirmed outbreak of H1N1 and meeting the case definition of an influenza-like illness is considered a suspect case pending laboratory confirmation.

For More Info:

A well summarized article from Pro-Med Mail, detailing events around the world related to Swine Flu

http://www.promedmail.org/pls/otn/f?p=2400:1001:6762198105018576::NO::F2400_P1001_BACK_PAGE,F2400_P1001_PUB_MAIL_ID:1010,77215

Check out Google Maps: http://maps.google.com/maps/ms?ie=UTF8&hl=en&t=p&msa=0&msid=106484775090296685271.0004681a37b713f6b5950&ll=32.639375,-110.390625&spn=15.738151,25.488281&z=5 for a realtime map of the world showing confirmed cases in purple, suspect cases in pink and deaths do not have a black dot.

Why Swine flu is called “Swine Flu”

Still more problems as Swine flu seems to be spread to new areas.  A very nice post from Pro-med mail  looks at why Swine Flu takes this name. 

In 1918-1919 the Spanish Flu caused significant death and morbidity in both human and swine populations, although it is likely to have originated from birds.  “Swine Flu” is bascially any virus that circulates through pig populations, such as H3N2, H1N2 or the present H1N1.  The terms H and N stand for haemagluttin and neuraminidase, which are unique ways influenza viruses infect humans.

This particular strain of H1N1 influenza nicknamed Swine Flu is able to be transferred between persons, without swine contact.  Further, there is a lack of evidence showing the initial jump from swine populations to humans.  H1N1 also carries a component of bird flu, as well.  Thus, simply calling it swine flu is inaccurate.

Swine Flu Outbreak in USA and Mexico 4/25/2009

Pig problems?For those who have been hearing about this on media sources such as CNN, I thought this might be of interest.  An outbreak of Swine Flu (H1N1) has been reported in several states of Mexico including Mexico City.  The outbreaks in Mexico appear to be carrying a case fatality rate of around 7% with 68 deaths and approx. 1,000 cases reported.  The cases reported in the USA were in San Diego and Texas, with no fatalities yet reported in America.  The strains of the viruses isolated thus far has proved to be similiar, both from America and Mexico.

Here are some decent links:

World Health Organization Influenza Outbreak in USA and Mexico  http://www.who.int/csr/don/2009_04_24/en/index.html

CDC Travel health Precaution for Mexico  http://wwwn.cdc.gov/travel/contentSwineFluMexico.aspx

 

There is no advice to postpone travel to Mexico and travelers should exercise “common sense” travel precautions such as frequent handwashing, avoidance of those with cough, sneeze or sniffles and low threshold for seeking medical care if fever and flu-like illness occurs.  Swine Flu appears to be sensitive to anti-virals such as Oseltamivir (tamiflu) and Zanamivir (relenza).  These medications are advised for treatment of swine-flu and should be started within the first day or two of symptoms.

Very interesting and scary stuff!  More to come…

Heat Illness: Prevention and Treatment

MirageAs the warm months of summer begin to draw closer and closer, getting outside and adventuring becomes a bit easier.  I personally love long runs in the hot part of the day and consider this my favorite time of year.  Physical exertion in a hot environment carries with it special risks and requires some knowledge about heat related illnesses and basic prevention.

Acclimatization to Heat

This is often a luxury adventurers do not have, especially when a traveler arrives to a new area and begins physical activity in a new and hot environment.  Typically, 8-10 days are required for a person to acclimatize to a hotter environment and daily exercise in the new environment can help the process.  Exercise for 30 minutes to 1 hour per day is generally sufficient.  As the body begins to acclimatize to the heat, it begins to sweat at a lower temperature, helping cool the body earlier.  Care should be taken to ensure adequate hydration, with oral water and sports drinks containing both sugar, salt and potassium.

The basic categories of heat illnesses can be divided up based on core body temperature and physical findings of the effected person.

Heat Exhaustion

  • Body temperature less than 39 C (102.2 F)
  • Presence of sweating
  • Increased heart rate (>100 beats per minute)
  • Normal mental status and awareness
  • Flu-like symptoms may be present such as malaise/fatigue, vomiting and weakness

Treatment of Heat Exhaustion centers around stopping physical exertion and getting the person into a cool and shaded environment.  Ensure adequate oral rehydration occurs and remove all restrictive and tight fitting clothing.  Ice packs may be placed on chest, arm pits and groin as these areas have blood vessels that run close to the surface and help facilitate cooling.  Wrap ice packs in towels to avoid skin damage from prolonged contact.  Lastly, spraying cool water on the patient and fanning them will help to reduce their body temperature quite rapidly as well.

Heat Stroke (True medical emergency)

  • Body temperature above 40.5 C (105 F)
  • Presence of sweating, severe cases may have absence of sweating
  • Increased heart rate (>100 beats per minute)
  • Changes in mental status (confusion, disorientation)
  • Difficulty walking
  • Low blood pressure

This condition is a true emergency and requires prompt medical care as this condition can be fatal.  Heat stroke occurs after the person passes through the first stage of heat exhaustion and does not receive proper treatment or continues to exert themselves in the heat.  Most experts agree that heat stroke can be diagnosed when changes in metal status occur in a patient with heat exhaustion.  Treatment centers around rapid re-cooling of the patient and the faster this occurs, the better the prognosis.  Icepacks (wrapped in towels) should be placed on groin, axillae and neck.  Spraying with cool water and fanning the victim is most effective in rapidly cooling the patient.  Intravenous fluids should be given and often require copious amounts to correct deficits.  Ensure their airway is protected if their mental status deteriorates or if vomiting occurs.  Seizures and shivering can be treated with benzodiazepines and oxygen should be given.  This person requires prompt transfer to a medical center and close monitoring.  Aggressive cooling should continue until core temperature drops to 38 C (100.4 F).

 

Tucson, ArizonaHeat Cramps

I think of heat cramps as a sign of dehydration and muscle fatigue in a hot environment.  Mild heat cramps can be treated by adequately rehydrating the person, generally with a commercial sports drink.  The key electrolytes are sodium and potassium, generally found in adequate concentration in products such as Gatorade.  I prefer to mix one half cup water with one half cup of electrolyte drink, due to increased osmolality of the sports drink.  Also, the sugars found in sports drinks help speed water into the bloodstream from the stomach.

 

Hyponatremia (low salt)

This is one of my favorite topics and frequently discussed in ultra-distance athletic events.  True hyponatremia occurs when the measurement of sodium in the blood drops below 130mEq/liter.  A frequent scenario that causes this is a person drinking large amounts of plain water to replace sweat losses which are high in sodium.  The person basically loses large amounts of sodium through sweat and water loss and replaces it with a low sodium concentration fluid, like plain water.  Difficulty can occur in differentiating heat stroke from hyponatremia and measurement of core body temperature can help with diagnosis.  Hyponatremia generally occurs in a setting of a normal core body temperature.  Treatment centers around providing intravenous re-hydration with normal saline fluid.  If the patient can take oral fluids, use a full-strength (non-diluted) sports drink for fluid replacement.  Prevention fo this can be accomplished by not only drinking adequate amounts of water but also regularly drinking a sports drink, before, during and after exercise.

Loa Loa: The “African Eye Worm”

Loa Loa migrating through eye

Loa Loa migrating through eye

Nicknamed “the African eye worm”, Loa loa is one of those tropical parasites that myths and legends are made of.  A medically important parasite from Africa, this is commonly a disease of local people but can effect travelers and adventurers in the endemic areas.

 Basics:

Also known as “African Eye Worm”. Filarial worms migrate through all tissues of the body. Transient swellings and itching are most common symptoms and can take years to appear.

 

Location:

African rainforests and especially Central Africa

 

Transmission/ Incubation:

Transmitted by the bite of an infected Deer Fly (Chrysops species)

Prevention:

Standard flying insect precautions, vector control, 300 mg once per week DEC (diethylcarbamazine) for high risk persons

 

Diagnosis:

Demonstration of microfilariae in daytime drawn blood smear

 

Treatment:

Diethylcarbamazine (DEC) 5-10 mg/kg three times per day for 3-4 weeks generally kills larvae and eliminates adult worms. Treat possible histamine/allergic based reactions with antihistamines/steroids. Albendazole and ivermectin may have a slower kill of larvae, causing a less severe treatment reaction.

 

Chrysops fly

Chrysops fly

This parasite is very similiar to the other nematodes including W. bancrofti.  however, this worm likes to move through tissues, without setting up a real permanent residency.  Soem trouble with this infection can occur when treatment begins.  Use of medications often used to treat other parasitic infections, found in the same geographic area, can cause bad reactions.  Caution should be used with ivermectine (treatment for onchocerciasis) as encephalitis/brain swelling can occur.  Common treatment reactions with DEC can involve histamine and typically respond well to antihistamines and/or steroids.

 

distribution of common parasitic infection

distribution of common parasitic infection

 

 

 

 

 

 

New vaccine for Japanese encephalitis approved in USA

Distribution of Japanese encephalitisJapanese encephalitis (JE) is a viral disease spread by mosquitoes (Culex) and found primarily in rural areas of Southeast Asia, although reports have been scattered all over Asia.  This infection has an affinity for the brain and spinal cord tissues as is know to causes meningitis like symptoms including headache, neck stiffness, fever and malaise.  A majority of these infections are asymptomatic although JE carries a 0.3-60% case fatality rate.  Infants are a particularly vulnerable population and often hardest hit.  Pigs and birds are a key reservoir of the illness, making visitors to rural farming areas at particular risk.  30,000 to 50,000 people are affected each year with 10,000 too 15,000 deaths.

The Vaccines:  

Japanese encephalitis is a vaccine preventable disease.  A vaccine is licensed in the USA, under the name JE-VAX  but has been difficult to obtain due to shortages and decreased production.   However, a new vaccine against Japanese encephalitis was approved by the FDA  March 31, 2009, called IXIARO and manufactured in the UK.  This will be the only vaccine against Japanese Encephalitis in the USA.  Research showed that only two doses of the newer generation vaccine were needed to provide adequate protection versus three does with JE-VAX.  A copy of the InterCell (manufacturer) press release can be read here

Who Needs It?

Most travelers to Asia do not require the JE vaccine.  This illness is not considered a risk for short-term travelers to urban areas and developed resort areas.  Those traveling to remote/rural areas (especially farming communities) during the rain season are the adventurers who should receive this vaccine.  Also, travel to an area with a previous outbreak of JE should prompt discussion about being vaccinated with your expedition/travel doctor.  Estimated risk of travelers to rural areas during transmission season is about 1 in 5,000 per day.

As with any mosquito-borne illness, preventing mosquito bites is a key step and should be done by all, regardless of being vaccinated.  Long sleeves and pants, avoiding peak biting times (dawn/dusk) and use of insect repellents are critical.  Bed nets are also another key ingredient for travelers sleeping in open areas.

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