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Cholera Outbreak in Misamis Oriental?

Posted Nov 21 2008 1:55pm

Is this the start of a new series of cholera outbreaks?

It is reported that almost 1,000 people in Misamis Oriental is stricken with cholera since November 15, Saturday, of which is described as the worst outbreak of the disease since 1975, according to health officials.  Patients are being attended to in the municipal hospital and in the local health units.  But with the overwhelming number of patients, all experiencing abdominal cramps and moderate to severe dehydration because of the “rice-water” stools, it is feared that medical supplies will run out before everyone is given the proper treatment.  Health workers even had to pitch tents outside the hospital just to be accomodate the other patients.  It’ll be a week more before the tests run by the epidemiologist, with regards to the real cause of the outbreak, comes out.  However, clinical manifestations of patients strongly points to a diagnosis of cholera.

At this point, it is important that a massive information drive be started to educate the local people about the importance of good sanitation, especially these days that cholera threatens the health and welfare of their provinces.  If we don’t start it now, neighboring places could be affected and it would be more difficult to quarantine the disease if larger areas, with more population, will be affected.

If my regular readers (you, you, you, the both of you.  Haha) remember, I wrote about the worst epidemic of Cholera in the Philippines as a contribution to the first TBR.  I described how patients, then, must have looked like and how the disease was dealt with by both the local and foreign physicians that resulted in the deaths of 200,000 people.

But, then, of course, it’ll be exerting too much effort to let you, readers, go to that 9-month old article and then come back here again.  So, I’ll try to give a summary of the facts regarding cholera, just to give you an idea why this is the most feared epidemic diarrheal disease.

from textbookofbacteriology.net

Cholera is caused by the organism Vibrio cholerae, a comma-shaped to rod-shaped, gram-negative aerobic bacillus with a single polar flagellum that thrives in brackish waters and in other bodies of water with poor sanitation.  It may also persist in shellfish and plankton.

The infectious dose required for the disease to manifest clinically depends on the mode of administration.  If water is ingested, there should be 10 3 -10 6 organisms to be considered an infectious dose.  If ingested through food (like a contaminated shellfish.  It was shown that Toxigenic V cholerae O1 can survive in crabs boiled for 8 minutes, but not in crabs boiled for 10 minutes ), fewer organisms (10 2 -10 4 organisms) are required to produce clinical manifestation of the disease.  Those who’re chronically taking antacids, H2 antagonists, or proton pump inhibitors are at increased risk of being affected due to low levels of acid in their stomach.  Studies have also shown that those with blood type O are at increased risk of developing clinical disease, as well, specifically El Tor Cholera. 

The organism can be isolated in the laboratory by using a selective medium such as TCBS (thiosulfate, citrate, bile salts, sucrose) agar, on which Vibrio form flat, yellow colonies, or taurocholate-tellurite-gelatin agar.  The organism may be detected directly with dark-field microscopy examination of a wet mount of fresh stool.  The serotype may be determined by using Inaba-specific or Ogawa-specific antiserum.

Motility provided by the flagellum enables the organism to penetrate the mucus layer of the intestines (but not penetrate the intestinal wall).  It elaborates mucinolytic enzymes, neuraminidase, and proteases, which further facilitates penetration of the mucus layer.

After ingestion of the organism, there will be 24 to 48 hours of incubation in which patient is still not manifesting clinically the infection.  After this period, patient will manifest the onset of watery diarrhea that is often followed by vomiting and abdominal cramps.  Fever is typically absent (though children may present with fever).

The main weapon of Vibrio cholerae is its enterotoxin (cholera enterotoxin, CT or choleragen) and it affects mostly the small intestine.  The enterotoxin is a protein molecule composed of 5 B subunits and 2 A subunits.  The B units are responsible for attachment of the organism to the ganglioside receptors (monosialosyl ganglioside, GM1) located on the surface of the cells lining the intestinal mucosa.  The A subunits are responsible for the increase in cyclic adenosine monophosphate (cAMP), which then blocks absorption of sodium and chloride by the microvilli of the intestinal mucosa trapping them within the intestinal lumen.  And since where sodium goes, water goes too, and thus, this setup encourages more secretion of water and electrolytes into the lumen, instead of being absorbed through the intestinal wall.  The result, thus, is the voluminous, watery diarrhea that looks like rice water (or the water that has been used to wash rice prior to cooking), which is characteristic of cholera.  Stool may also have a fishy odor.

And in patients who’re severely infected, the stool volume can exceed 250 mL/kg in the first 24 hours.  A classic picture of someone who has severe cholera diarrhea is that of a bedridden patient, with two intravenous lines for hydration (because he could no longer effectively hydrate orally), and with a pail beneath his bed with an appropriate hole for his continuous passage of watery stool he cannot afford to go to the bathroom anymore.  Without immediate replacement of lost fluids and electrolytes, patient could easily succumb to hypovolemic shock and eventually, death.  And with only 1-2 days of incubation period, it can easily infect a large number of people in a few days, if not specific preventive and therapeutic measures are taken.

So, the most important treatment in the management of cholera is prompt, proper hydration.  However, antibiotics like tetracycline, azithromycin, erythromycin, ciprofloxacin, norfloxacin, and furazolidone can help shorten the duration of the infection and hastens clearance of organism from the stool.

So, for outbreaks like this, it would be important to focus on sanitation to control the spread of the disease.  The Vibrio cholerae can get transmitted from an infected person through his stools that gets into a water source.  It would be practical to advice residents of affected area not to get their water for drinking and cooking from the water source where they also bathe and defecate.  People should also be educated about the importance of handwashing before eating or handling food and after attending to personal hygiene.  Fruits and vegetables should also be washed thoroughly before being eaten.  It would be prudent that, during outbreaks, only well-cooked food should be eaten.  If a patient dies of cholera, funeral and burial should be held as soon as possible, and the corpse disinfected using 2% chlorine solution and enclosed in a plastic bag.  Funeral and burial attendance and duration should be kept to a minimum, with respect to the community’s traditional practices.  All hygiene measures should be done from the preparation up to the burial.

For other critical steps and actions during acute diarrheal disease emergencies such as outbreaks, please do read in full this leaflet from WHO: Acute Diarrheal Disease in Complex Emergencies: Decision Making for preparedness and response.  It is a good guide for health care workers and the rest of the community.

There is also actually an oral vaccine for cholera that is recommended to those who’ll be visiting endemic or epidemic areas.  The vaccine is called Dukoral and is available in the country in suspension form and given to adults in 2 doses and children from 6 years of age.  Children 2-6 years of age are recommended to have 3 doses.  Booster doses are given to adults  and >6 years of age after 2 years and to children aged 2-6 years, after 6 months.  However, it only confers protection to a specific serotype of Vibrio cholerae only.  Also, it does not confer complete protection and it is still strongly recommended to follow the standard safety precautions, especially when travelling to areas where cholera is endemic or epidemic.  Also, the vaccine may not be given to those who have the acute infection.

As for what is happening now in Misamis Oriental, it’ll be hard enough propelling a massive information drive and more difficult to be able to resolve quickly the chronic problem of sanitation in the underprivileged areas.  Most people have already gotten used to their old ways, drinking, bathing, defecating, and urinating in the same water source.  And even if there are village that persevere in maintaining their water and food sanitation, lack of resources and poverty has often prevented them from doing so.  This will be the challenge now to the local health units and most especially, to the Department of Health, since most of the local health units shall now depend upon the supplies that will come from them.

My hope is that through appropriations of enough medicines, treatment, and other supplies, and continuing health education, this cholera outbreak will be prevented from spreading to other areas and eventually, developing into an epidemic.  Let us also hope that our country will not go the way of Zimbabwe, which currently is facing a crisis in its fight against the spread of cholera, with 1.4 M people being threatened with the disease, because of continuing breakdown in sanitation, lack of medical supplies and the health care workers remaining overworked and underpaid.

References:

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