Travellers Diseases - The Travel Doctor

Typhoid Fever

Typhoid fever is a life-threatening illness caused by the bacterium Salmonella Typhi. It belongs to the Salmonella group which contains nearly 2,000 different types causing mild diseases such as food poisoning, through to the more serious disease of typhoid fever. Paratyphoid fever is a similar but less severe variant.

It is a common illness in the developing world, where it affects about 12.5 million people each year.

Typhoid fever occurs in most parts of the world except in developed countries such as the United Kingdom, Western Europe, USA, Canada, Australia, New Zealand and Japan. Therefore, if you are traveling to the developing world, you should consider taking precautions. Travellers to Asia, Africa, and Latin America are especially at risk.

The typhoid fever bacteria is carried in the bloodstream and intestinal tract of infected persons. A small number of persons, called carriers, recover from the fever but continue to carry the bacteria. Both ill persons and carriers shed the bacteria in their feces. Diagnosis requires medical opinion and examination of the blood.

You can get typhoid fever if you eat food or drink beverages that have been contaminated by a person who is shedding S. Typhi or if sewage contaminated with S. Typhi bacteria gets into the water you use for drinking or washing food. Therefore, typhoid fever is more common in areas of the world where handwashing is less frequent and water is likely to be contaminated with sewage.

The incubation period depends on the quantity of the bacteria swallowed and can vary from one to three weeks.

Persons with typhoid fever usually have a sustained fever as high as 39° or 40° C. They will also feel weak, have stomach pains, headache and loss of appetite. In some cases, patients have a rash of flat, rose-colored spots.

Treatment: Typhoid fever is usually treated with antibiotics such as ampicillin or ciprofloxacin which are very effective but should ideally be given under medical supervision. Hospital admission may be more appropriate abroad. Persons treated with antibiotics usually improve within 2 to 3 days, and deaths rarely occur. However, relapse is not uncommon and patients may develop the carrier state after treatment. It is therefore very important to have your stools examined on your return if you have been treated for typhoid abroad.

Without treatment this illness can be fatal!!. Persons who do not receive treatment may continue to have the fever for weeks or months, and as many as 20% may die from complications such as peritonitis resulting from perforation of the gut wall.

Typhoid fever can be prevented and can usually be treated with antibiotics. If you are planning to travel to a region where it exists, you should know about it and what steps you can take to protect yourself.

There are two basic actions that can help to protect you from typhoid fever:

1. Get vaccinated against typhoid fever.
2. Avoid risky foods and drinks.

Watching what you eat and drink when you travel is just as important as being vaccinated. This is because the vaccines are not completely effective. Avoiding risky foods will also help protect you from other illnesses, including travelers' diarrhoea, cholera, dysentery, and hepatitis A.

Tetanus

Tetanus is a potentially fatal disease which is caused by an infection of the bacterium Clostridium Tetani. The bacteria enter the body through a wound where they grow and produce a powerful toxin which circulates in the blood and causes muscular rigidity and painful muscle contractions. Death is usually caused by respiratory problems and exhaustion.

Tetanus spores are present in soil worldwide and may be introduced into the body during injury through a puncture wound, burn or trivial, unnoticed wounds.

Tetanus can be contracted quite easily through a small wound such as a scratch through which the organism can get into the body. There have been reported cases of tetanus in which the patient cannot even remember the injury since it was so small and insignificant.

While vaccination has largely diminished the incidence of tetanus, the disease has not disappeared.

If individuals are not fully immunised there is always the risk of tetanus developing in wounds contaminated by soil. The incubation period is between four and twenty one days, commonly around ten days.

The first sign of tetanus is when the patient may notice jaw stiffness and difficulty in opening the mouth (lock jaw).

Treatment: Requires medical supervision in hospital.

Prevention: All wounds, even minor ones should be thoroughly washed with clean water and soap taking particular care to remove all dirt and loose tissue.

Immunisation against tetanus is highly protective and adults and children should ensure they are in date for it. Booster doses should be given at ten year intervals.

Booster doses in addition to five doses are not recommended except in the case of the treatment of a tetanus-prone wound.

The Department of Health advised in 2002 that tetanus vaccine is to be replaced by the combined tetanus/low dose diphtheria vaccine for adults and adolescents for routine use and for travel vaccination. Stocks of single tetanus vaccine are now exhausted and companies are no longer supplying this product.

Poliomyelitis (polio)

Poliomyelitis, normally referred to as polio is caused by a virus which is spread from person-to-person primarily through faecal contamination of food and water although it can also be spread by droplet transfer.

Initially, infection of the gut can spread to the spinal cord or brain where it can cause paralysis. In the days before widespread vaccination it tended to occur in epidemics.

Travellers who have not been immunised or whose immunity has waned are at risk if they are travelling to areas of the world where polio still occurs. ie. Nigeria, Niger, India, Pakistan and Afghanistan are particularly high risk.

In many cases infection with the polio virus is asymptomatic. When symptoms do occur, the onset of polio is sudden with fever, headache, nausea and vomiting as the virus multiplies in the gut. The virus then invades the blood stream and nervous system.

Paralysis occurs in less than 1 in 100 cases of infection. This risk increases with age. The patient may die if the respiratory and swallowing muscles are affected. Those who survive may develop residual paralysis. Severe pain, and wasting are common in paralysed muscles. Recovery can take up to a year.

The incubation period is 7-14 days. A blood test for antibodies will confirm the diagnosis, although this is not always available abroad. Patients are infectious by close contact and should be isolated for at least a week.
Treatment: The development of paralysis is clearly an emergency and medical help should be sought without delay. If the paralysis affects the breathing muscles, artificial means of respiration may be required. Extreme care should be taken when disposing of excreta for up to 6 weeks.

Prevention: There is an effective vaccine available. Ten yearly boosters should be given to ensure maximum immunity and travellers should ensure they are in date for polio immunisation.

Past infection with polio does not always give complete protection as there are three strains of the virus.

As the disease is usually spread through close contact, try to avoid crowded places in high risk areas as much as possible. (buses, trains,public swimming pools). This could prove difficult in some countries such as India. Therefore vaccination would be imperative if travelling there.

The World Health Organisation is making great efforts to encourage widespread use of polio vaccine in an attempt to eradicate polio from all the countries of the world. Many countries have already been certified polio free by the WHO. By 1994, the Americas were certified as polio-free.

Hepatitis A

This is a viral disease that causes inflammation of the liver. It occurs worldwide and is especially prevalent in areas of poor sanitation and hygiene.

Many children in developing countries are infected with the virus at an early age, usually without symptoms. Past infection with hepatitis A virus gives life long immunity.

However, in the developed world where sanitation is better, fewer people are contracting the disease during childhood and are therefore at risk when they become adults from the more severe form of the disease, which they could catch when they travel to areas of the world where hepatitis A is more common. The map below shows the global incidence of Hepatitis A.

The virus is transmitted from person-to-person by the faecal-oral route particularly in areas with poor sanitation and overcrowding. It is quickly spread through close contact, particularly within families and institutions and is commonly associated with eating and drinking contaminated food and water. Food outbreaks are often linked to raw or undercooked shellfish and raw vegetables although almost any food can be implicated which has been poorly cooked in sewage-polluted water.

Hepatitis A has a wide range of symptoms, from an infection without any noticeable symptoms through to jaundice, liver failure and death. Unlike hepatitis B, there is no chronic carrier state for hepatitis A.

Symptoms include fever, chills, weakness, loss of appetite, nausea and abdominal discomfort, followed within a few days by jaundice (yellowing of the skin and eyes). The urine becomes dark and the stools pale. Jaundice may be severe and prolonged and complete liver failure may occur.

Prevention: Avoid contaminated food and water.

Hepatitis A can be prevented by vaccination. The immunisation schedule consists of a single dose of vaccine followed by a booster dose six to twelve months after the first dose to give immunity up to ten years.

Cholera

Cholera is a bacterial infection of the gastro-intestinal tract caused by the bacterium Vibrio Cholerae.

These bacteria are typically ingested by drinking water contaminated by improper sanitation or by eating improperly cooked fish, especially shell fish.

About one million Vibrio cholerae bacteria must be ingested to cause cholera in normally healthy adults, although increased susceptibility may be observed in those with weakened immune systems, individuals with decreased gastric acidity (as from the use of antacids etc.), or those who are malnourished. The incubation period is usually two to three days but may only be a few hours.

Symptoms range from the mild to the severe which may be fatal and include; diarrhoea, abdominal cramps, nausea, vomiting, and dehydration.

Vibrio cholerae causes the disease by producing a toxin that induces severe painless watery diarrhoea of sudden onset, occasionally accompanied by vomiting, which rapidly leads to dehydration. The profuse diarrhoea allows the bacterium to spread to other people under insanitary conditions.

The bacteria are transmitted in water or food contaminated with infected faeces and the disease can occur in large-scale epidemics where sanitary conditions have broken down such as those in areas of natural disasters.

Cholera is rare amongst travellers as they tend to avoid the insanitary conditions which would put them at risk.

Treatment: Medical help should be sought without delay. Cholera is treated with rehydration and antibiotics, but in severe cases, can lead to death.

Fluid replacement is essential and should be started as soon as symptoms occur. The patient should aim to drink as much non-alcoholic fluid as it takes to maintain a good output of normal looking urine (this may be as much as six or seven litres a day).

Prevention: Avoid contaminated food and water, especially raw or undercooked seafood from polluted water.

There is a new vaccine (Dukoral) for immunisation against cholera for people travelling to highly endemic or epidemic areas, particularly emergency relief and health workers in refugee situations. The vaccine may be considered for the following:

People working in areas where there are known cholera outbreaks (e.g. aid workers).
Travellers staying for long periods in known high risk areas and/or where close contact with locals is likely, and who do not have access to medical care.
Travellers to risk areas who have an underlying gastro-intestinal disease or immune suppression.

The vaccine is taken as a raspberry flavoured drink and can be used in adults and children over 2 years.

It is not currently licensed in the UK for travellers diarrhoea.

Meningitis (Meningococcal)

Meningitis is an infection that causes inflamation of the membranes and fluid that surrounds the brain and spinal cord. It can be caused by a viral or bacterial infection.

Viral meningitis is generally less severe and resolves without specific treatment, while bacterial meningitis (meningococcal) can be quite severe and may result in brain damage, coma or even death.

It can occur in epidemics, especially where large crowds are gathered, as it is acquired through direct contact or inhalation of bacteria in droplets coughed or sneezed into the air.

Early diagnosis and treatment are very important. If symptoms occur, the patient should seek medical help immediately. Medical supervision is required since large doses of antibiotics are employed. Treatment should be started without delay. Identification of the type of bacteria responsible is helpful for the selection of correct antibiotics.

High fever, headache, and stiff neck and a blotchy rash are common symptoms. These can develop over several hours, or they may take 1 to 2 days. Other symptoms may include nausea, vomiting, discomfort with bright lights, confusion, and sleepiness. As the disease progresses, patients may develop seizures before going into a coma.

Sporadic cases of meningitis are found worldwide. In temperate zones, most cases occur in the winter months. Localized outbreaks occur in enclosed crowded spaces (e.g. dormitories, military barracks). In sub-Saharan Africa, in a zone stretching across the continent from Senegal to Ethiopia (known as the African “meningitis belt”), large outbreaks and epidemics take place during the dry season (November–June).

Bacterial meningitis is contagious. The bacteria are spread by direct person to person contact including aerosol transmission and exchange of respiratory and throat secretions (i.e. sneezing, coughing, kissing, etc.).

Fortunately, none of the bacteria that cause meningitis are as contagious as the viruses that spread the common cold or influenza, and they are not spread by casual contact or by simply breathing the air where a person with meningitis has been.

The risk to travellers is generally low. However, the risk is considerable if travellers are in crowded conditions or taking part in large population movements such as pilgrimages eg. the Haj to Mecca. Localized outbreaks occasionally occur among travellers (usually young adults) in camps or dormitories. Backpackers who use crowded hostels will be at greater risk during an outbreak

Prevention: Avoid overcrowded places and close contact with the local population.

There are two vaccines used to protect travellers. The meningitis A + C vaccine and the meningitis ACWY vaccine. The latter is required for pilgrims and seasonal workers visiting Saudi Arabia.

Effective treatment is undertaken with a number of antibiotics. It is important, however, that treatment be started early in the course of the disease. This will reduce the risk of mortality to below 15%, although the risk is higher among the elderly.

Diphtheria

Diphtheria is an infection caused by a bacterium called Corynebacterium diphtheriae that causes a moderately sore throat. Sometimes the lining of the throat may swell to form "a false membrane" which can cause difficulties in breathing.

In its early stages, diphtheria may be mistaken for a severe sore throat. In severe cases the neck tissue may become very swollen and in tropical countries the infection can occur in skin ulcers.

It is mainly spread by droplets expelled from the nose and mouth usually by breathing in diphtheria bacteria after an infected person has coughed, sneezed or even laughed. It can also be spread by handling used tissues or by drinking from a glass used by an infected person.

Nearly one out of every ten people who get diphtheria will die from it. Most cases occur among unvaccinated or inadequately vaccinated people.

The bacterium produces a toxin which can seriously damage the heart muscle and the nervous system.

After two to six weeks, the effects of the toxin produced by the bacteria become apparent with severe muscle weakness, mainly affecting the muscles of the head and neck. Inflammation of the heart muscle can cause heart failure.

Death usually occurs either from respiratory failure, heart failure or a build up of toxin in the nervous system.

Whether or not the patient dies depends on the severity of the illness, their level of immunity and the speed with which treatment is started.

One of the regions where diphtheria is present is eastern Europe, including Russia and the former states of the Soviet Union. Cases of have occurred in Finland, Estonia, Poland and Belarus and even Germany, Belgium and the UK resulting from imported infection.

Treatment: This is specialised and requires medical supervision in hospital.

Prevention: Try to avoid too close contact with people in crowded places when travelling in endemic regions (particularly kissing and sharing bottles or glasses).

Diphtheria can be prevented with a safe and effective vaccine. A vaccine is now available for travellers to provide protection against both diphtheria and tetanus.

Immunisation is very effective and UK children are immunised within their first year. Boosters are required every 10 years for travellers and those at risk.

Rabies

This is a viral infection that is acquired from the saliva of an infected or rabid animal, usually a dog or cat. In most cases infection results from a bite but even a lick on an open cut or sore may be enough.

Symptoms start with itching and tingling at the site of the healed bite and then rapidly progresses to include headache, fever, spreading paralysis, confusion, aggression and hydrophobia (fear of water).

It may take many weeks or months for symptoms to develop although it is usually two to eight weeks. Animals may be infectious for five days before they develop symptoms.

Treatment: Thoroughly cleanse all bites with soap and water and do not allow the wound to be stitched. Limited bleeding should be encouraged. Apply alcohol if possible.

If available human immunoglobulin (HRIG) should be given especially for bites to the head/face. The disease can almost always be prevented, even after exposure, if the vaccine is administered without delay.

You should therefore seek medical advice immediately and have a course of 5 injections of Purified Chick Embryo Cell Vaccine (PCEC) or Human Diploid Cell Vaccine (HDCV). This can be difficult to obtain abroad and if necessary the British Embassy or consulate should be contacted for a supply.

If you have had a pre-exposure course of vaccine you should still have a 'booster' course of 2 doses of vaccine without delay.

Prevention: Never approach or handle animals you don't know, particularly if they are acting strangely.

Pre-exposure immunisation against rabies is recommended for long-stay travellers/residents and those who intend to travel to rural and remote areas.

In the event of a bite, your body's responses could be quickly activated by booster doses of vaccine. There are rarely any side effects or discomfort from the new type of vaccine unlike the old types.

Tuberculosis (TB)

Tuberculosis (TB) is an airborne, infectious disease caused by a bacterium called Mycobacterium tuberculosis which primarily affects the lungs.

While both preventable and curable, TB remains one of the world’s major causes of illness and death.

Approximately one-third of the world’s population carry the TB bacteria, almost 9 million of whom develop “active” TB each year, which can then be spread to others.

The disease is usually spread through infected sputum but there is a form spread through milk from infected cows.

Transmission is usually spread by inhalatation of microscopic droplets that come from a person infected with TB. When coughing, speaking or sneezing, small droplets are expelled into the air which quickly dry out but the bacteria can remain airborne for hours.

After the tuberculosis bacteria have been inhaled, they invade the lungs, and within approximately six weeks a small infection appears which rarely gives any symptoms but sometimes general malaise, weakness and weight loss are characteristic during the incubation period which may be up to twelve weeks. After this, the bacteria can then spread through the blood.

The infection remains dormant in most cases in people who are otherwise healthy and does not do any obvious harm. Months or even years later, however, the disease can become reactivated in different organs if the immune system is weakened. The lungs are the favourite place for the illness to strike.

Typical symptoms of TB include:

TB usually develops slowly and symptoms might not begin until months or even years after initial exposure to the bacteria.

In some cases the bacteria infect the body but don't cause any symptoms, which is known as latent TB. If the bacteria do cause symptoms it is active TB.

You should see a GP if you have a cough that lasts more than three weeks or if you cough up blood or have any of the above symptoms and have been in contact with someone who has the disease.

The bacteria can spread to the blood in individuals who have weak immune systems (especially when caused by alcohol or HIV).

TB is primarily a disease of the lungs. However, the infection can spread via blood from the lungs to other organs in the body, the bones, the urinary tract and sexual organs, the intestines and even in the skin. Lymph nodes in the lungs and throat can also get infected.

Sometimes the disease can be overwhelming; producing meningitis and coma; this particularly dangerous form is usually found in children and those who have not previously been vaccinated or exposed to the disease.

TB is found in every country in the world, but the majority of TB cases are concentrated in developing countries, particularly those in Asia and Africa. It is a serious condition but can be cured with proper treatment.

Three million deaths occur each year from TB, which is more than any other single infectious disease. The disease is more common in areas of the world where poverty, malnutrition, poor general health and social disruption are present. The disease has been commonly found in places of crowding such as hostels and prisons where healthcare is poor.

Treatment: Treatment with antibiotics is effective but is prolonged.

Effective and affordable antimicrobial drugs to treat TB disease have been available for decades but these must be taken for six to eight months under medical supervision because if treatment is not completed, the emergence of drug-resistant strains of the TB bacteria may be encouraged. These medicines may not always available abroad.

With treatment, a TB infection can usually be cured. Several different antibiotics are used. This is because some forms of TB are resistant to certain antibiotics. If you are infected with a drug-resistant form of TB, treatment can last as long as 18 months.

The usual course of treatment is:

After taking the medicine for two weeks, most people are no longer infectious and feel much better. However, it is important to continue taking the medicine exactly as prescribed and to complete the whole course of antibiotics.

It may be several weeks or months before a person starts to feel better. The exact length of time will depend on your overall health and the severity of your TB.

If you have been in close contact with someone who has TB, tests may be carried out to see if you are also infected.

These can include a chest X-ray, sputum tests, blood tests and a skin test.

Prevention: Travelers should try to avoid exposure to TB patients in crowded environments (such as hospitals, prisons, or homeless shelters). Avoid other overcrowded places, particularly where spitting is common.

The risk of TB transmission on an aeroplane does not appear to be higher than in any other enclosed space.

To prevent TB transmission, people who have infectious TB should not travel by commercial aircraft or other commercial conveyances.

Never drink unpasteurised milk. If in doubt, boil it before drinking.

There is a vaccination against TB which can give a valuable degree of protection, particularly in children.

Those who have not received BCG immunisation are advised to do so and if for travel purposes, at least six weeks before departure to ensure a protective level of immunity.

Schistosomiasis

Also known as bilharzia, is a disease caused by parasitic worms called schistosoma. They belong to the family of flat worms known as trematodes or flukes. There are several different species e.g. S. mansoni, S. haematobium, and S. japonicum. About 200 million people are thought to be infected world-wide.

The infection occurs when the skin comes into contact with contaminated fresh water which contains a certain type of snail that carry the schistosomes.

Fresh water becomes contaminated by Schistosoma eggs when people who are infected urinate or defaecate in the water. The eggs then hatch, and if the snails are present in the water, the parasites invade the snails and grow and develop inside them. The parasites eventually leaves the snails and enter the water where they can survive for up to 48 hours.

Schistosoma parasites can penetrate the skin of persons who are wading, swimming, bathing, or washing in contaminated water. Within several weeks, worms grow inside the blood vessels of the body and produce eggs. Some of these eggs travel to the bladder or intestines and are passed into the urine or stools.

Symptoms: Within days after becoming infected, a rash or itchy skin may develop. Fever, chills, cough, and muscle aches can begin within 1-2 months of infection. Most people have no symptoms at this early phase of infection.

Eggs travel to the liver or pass into the intestine or bladder. Rarely, eggs are found in the brain or spinal cord and can cause seizures, paralysis, or spinal cord inflammation. For people who are repeatedly infected for many years, the parasite can damage the liver, intestines, lungs, and bladder.

The symptoms of schistosomiasis are caused by the body's reaction to the eggs, not by the worms themselves.

Anyone travelling to areas where schistosomiasis occurs and whose skin comes in contact with fresh water from canals, rivers, streams, or lakes, is at risk of getting schistosomiasis.

If someone does develop any of the symptoms after visiting one or more of the countries where schistosomiasis is found and was in contact with fresh water, they should go immediately to their doctor and describe in detail where and for how long they travelled and that they may have been exposed to contaminated water.

They will need to provide a stool or urine sample for analysis to see if you the parasites are present. A blood test has also been developed but there should be a six to eight week interval after the last exposure to contaminated water before the blood sample is taken.

Avoid swimming or wading in fresh water when you are in countries in which schistosomiasis occurs. Swimming in the ocean and in chlorinated swimming pools is generally thought to be safe.
Drink safe water. Because there is no way to make sure that water coming directly from canals, lakes, rivers, streams or springs is safe, you should either boil water for 1 minute or filter the water before drinking it.
Boiling water for at least 1 minute will kill any harmful parasites, bacteria, or viruses present. Iodine treatment alone WILL NOT GUARANTEE that water is safe and free of all parasites
Bath water should be heated for 5 minutes at 65 degrees Celsius. Water held in a storage tank for at least 48 hours should be safe for showering.
Vigorous towel drying after an accidental, very brief water exposure may help to prevent the Schistosoma parasite from penetrating the skin but you should NOT rely on vigorous towel drying to prevent schistosomiasis.
There is no vaccine available.

Treatment: A safe and effective treatment of schistosomiasis is available. Praziquantel is effective against all human schistozomes. Treatment is usually for one or two days and no serious toxic effects have been reported.

Areas of the world where schistosomiasis occurs:-

Africa: north Africa, southern Africa, sub-Saharan Africa, Lake Malawi, the Nile River valley in Egypt.

South America: including Brazil, Surinam, Venezuela.

Caribbean: Antigua, Dominican Republic, Guadeloupe, Martinique, Montserrat, Saint Lucia.

The Middle East: Iran, Iraq, Saudi Arabia, Syria & Yemen.

Southeast Asia: India, Bagladesh, Central Indonesia, the Philippines, Thailand, Laos, Cambodia, Vietnam (the Mekong Delta), Southern China & Japan.

Leptospirosis (Weil's disease)

Leptospirosis is a bacterial disease caused by bacteria of the genus Leptospira. It affects humans and animals and causes a wide range of symptoms, including high fever, severe headache, chills, muscle aches, and vomiting, and may include, red eyes, abdominal pain, diarrhea, or a rash although some infected persons may have no symptoms at all. If the disease is not treated, then kidney damage, meningitis liver failure, respiratory distress and even death may result.

Outbreaks of leptospirosis are usually caused by exposure to water contaminated with the urine of infected animals. Many different kinds of animals carry the bacteria such as cattle, pigs, horses, dogs, rodents, and wild animals.

Humans become infected through contact with water, food, or soil containing urine from these infected animals. This may happen by swallowing contaminated water or through cuts and contact with broken skin. The disease is not spread from person to person.

The incubation period is anything from two days to four weeks. The illness usually begins abruptly with fever and other symptoms. Leptospirosis may occur in two phases; after the first phase, with fever, chills, headache, muscle aches, vomiting, or diarrhoea, the patient may recover for a time but become ill again.

If a second phase occurs, it is more severe; the person may have kidney or liver failure or meningitis. This phase is also called Weil's disease. Diagnosis of Leptospirosis is confirmed by laboratory testing of a blood or urine sample.

Leptospirosis occurs worldwide but is most common in temperate or tropical climates. It is an occupational hazard for many people who work with animals, such as farmers, sewer workers, veterinarians, fish workers, dairy farmers, or military personnel.

It is a recreational hazard for campers or those who participate in outdoor sports in contaminated areas and has been associated with swimming, wading, and whitewater rafting in contaminated lakes and rivers.

Leptospirosis can be effectively treated with antibiotics, such as doxycycline or penicillin, which should be given as early as possible in the course of the disease. Intravenous antibiotics may be required for persons with more severe symptoms. Persons who are thought to have symptoms suggestive of leptospirosis should seek medical help immediately.

Ebola Virus, Lassa Fever & Marburg Virus (the really nasty viruses)

Ebola Virus

Ebola Hemorrhagic Fever is a severe, often-fatal disease that has appeared sporadically since its initial recognition in 1976.

The disease is caused by infection with Ebola virus, named after a river in the Democratic Republic of the Congo in West Africa, where it was first recognized. The virus is one of two members of a family of RNA viruses called the Filoviridae. There are four identified subtypes of Ebola virus. Three of which have caused disease in humans.

Infections with Ebola virus are acute. There is no carrier state. Because the natural reservoir of the virus is unknown, the manner in which the virus first appears in a human at the start of an outbreak has not been determined. However, it is thought that the first patient becomes infected through contact with an infected animal, possibly a primate or a fruit bat. Infection can occur from ingestion of infected meat.

Most of the previous outbreaks have been caused by meat from dead infected animals collected by hunters who then sell it on. Fruit bats are also widely eaten in rural west Africa – either smoked, grilled or in a spicy soup.

After the first patient in an outbreak setting is infected, the virus can be transmitted in several ways. People can be exposed to Ebola virus from direct contact with the blood and/or secretions of an infected person. Thus, the virus is often spread through families and friends because they come in close contact with such secretions when caring for infected persons. People can also be exposed to Ebola virus through contact with objects, such as needles, that have been contaminated with infected secretions. Health workers who treat ebola patients are also at risk and should always wear specialised protective clothing when treating an infected person.

The incubation period for Ebola HF ranges from 2 to 21 days. The onset of illness is abrupt and is characterized by fever, headache, joint and muscle aches, sore throat, and weakness, followed by diarrhoea, vomiting, and stomach pain. A rash, decreased kidney and liver functioning, red eyes, hiccups and internal and external bleeding may be seen in some patients.

Researchers do not understand why some people are able to recover from Ebola HF and others are not. However, it is known that patients who die usually have not developed a significant immune response to the virus at the time of death.

There is no standard treatment for Ebola HF. Patients must be isolated and receive supportive therapy. This consists of balancing the patient’s fluids and electrolytes, maintaining their oxygen status and blood pressure, and treating them for any complicating infections.

How Ebola kills:

Once the Ebola virus makes its way into the body, it gets into the body's cells and replicates itself. Then it comes bursting out of the cells and produces a protein called ebolavirus glycoprotein that wreaks havoc. The ebolavirus glycoprotein, attaches to the cells on the inside of blood vessels. This increases the permeability of the blood vessels leading to blood leaking out of the vessels. The virus also disrupts the body's ability to coagulate and thicken the blood. Even people who don't show hemorrhagic symptoms will experience this leaking of blood from the vessels which can eventually lead to shock and, ultimately, death.

The Ebola virus is also a master of evading the body's natural defences: It blocks the signaling to cells called neutrophils, which are white blood cells that are in charge of raising the alarm for the immune system to come and attack. In fact, Ebola will infect immune cells and travel in those cells to other parts of the body, including the liver, kidney, spleen and brain.

Each time one of the cells is infected with the Ebola virus and bursts open spilling out its contents, the damage and presence of the virus particles activates molecules called cytokines. In a healthy body, these cytokines are responsible for provoking an inflammatory response so that the body knows it's being attacked. But in the case of an Ebola patient it is the overwhelming release of cytokines which cause the flu-like symptoms that are the first sign of Ebola infection.

The prevention of Ebola HF in Africa presents many challenges. Because the identity and location of the natural reservoir of Ebola virus are unknown, there are few established primary prevention measures.

There is currently no vaccine that protects against the Ebola virus.

Education regarding infection control measures to prevent the spread of the virus is of paramount importance.

Unless you are travelling to an area where an Ebola outbreak is occurring and/or you have direct contact with an ill individual infected with Ebola, the risk of acquiring Ebola virus is extremely low.

Lassa fever

is an acute viral illness that occurs in West Africa. The illness was discovered in 1969 and named after the town in Nigeria where the first cases originated. The virus, a member of the virus family Arenaviridae is animal-borne and is acquired from a particular kind of wild rodent known as the multimammate rat.

In the areas of Africa where the disease is endemic, Lassa fever is a significant cause of mortality. While it is mild or has no observable symptoms in about 80% of people infected, the remaining 20% contract a severe multisystem disease. Lassa fever is also associated with occasional epidemics, during which the case-fatality rate can reach 50%.

The disease is known to be endemic (constantly present) in Nigeria, Sierra Leone, Liberia, Guinea and the Central African Republic, and there is evidence of infection in nearby countries including Mali, Senegal, and the Democratic Republic of Congo. However, because the rodent species which carry the virus are found throughout West Africa, the actual geographic range of the disease may extend to other countries in the region.

The virus is shed in the urine and droppings of infected rats (which are infected for life), and most infections arise through contact with materials contaminated by these.

Lassa fever may also spread through person-to-person contact. This type of transmission occurs when a person comes into contact with virus in the blood, tissue, secretions, or excretions of an individual infected with the Lassa virus.

The virus cannot be spread through casual contact (including skin-to-skin contact without exchange of body fluids). The virus is present in semen for up to three months after the disease begins, thus sexual transmission can also occur. It may also be spread by contaminated medical equipment, such as reused needles etc.

Marburg Virus

Marburg haemorrhagic fever is a rare, severe type of haemorrhagic fever which affects both humans and animals. It is caused by a genetically unique RNA virus of the filovirus family, and its recognition led to the creation of this virus family. The Ebola virus is the only other known member of this family.

Marburg virus is indigenous to Africa but the actual geographic area to which it is native is unknown, but could include parts of Uganda and Western Kenya, and Zimbabwe. As with Ebola virus, the actual animal host for Marburg virus also remains a mystery.

Just how the virus is first transmitted to humans is unknown. However, as with some other viruses which cause haemorrhagic fever, humans who become ill with Marburg fever may spread it to other people.

After an initial incubation period of five to ten days, the onset of the disease is sudden and is marked by fever, chills, headache, and myalgia. Around the fifth day after the onset of symptoms, a rash appears, most prominent on the chest, back, stomach. Nausea, vomiting, a sore throat, chest pain, abdominal pain, and diarrhoea may then appear. Symptoms become increasingly severe and may include jaundice, inflammation of the pancreas, severe weight loss, delirium, shock, liver failure, multi-organ dysfunction and even death.

Because many of the signs and symptoms of Marburg fever are similar to those of other diseases, such as malaria or typhoid fever, diagnosis of the disease can be difficult, especially if only a single case is involved.

A specific treatment for this disease is unknown. However, supportive hospital therapy is required. This includes balancing the patient's fluids and electrolytes, replacing lost blood and clotting factors, maintaining their blood pressure, and treating them for any complicating infections.

Due to our limited knowledge of the disease, preventive measures against transmission from the original animal host have not yet been established. Measures for prevention of secondary transmission are similar to those used for other haemorrhagic fevers.