Diphtheria

Introduction

Diphtheria is a bacterial disease caused by Corynebacterium diphtheriae. This disease occurs worldwide but it is especially prevalent in poor countries where there is low vaccine coverage. A widespread and effective vaccination programme has resulted in diphtheria being rare in resource-rich countries. Incidence of diphtheria may occur in unvaccinated travellers to endemic areas, with those spending prolonged periods with those individuals at risk. Travel and close contact with cattle or other farm animals including cats and dogs, are a potential risk factor for infection.

Transmission

Diphtheria is spread between humans through respiratory droplets, contaminated fomites or from exudates from infected skin lesions during close physical contact. Poor hygiene practices and conditions of crowding can also increase the risk of transmission.

Signs and symptoms

The incubation period is between two and seven days. The symptoms are classified as local or systemic, depending on whether or not the exotoxins have spread. There are several syndromes associated with respiratory tract diphtheria, with the most common being pharyngeal diphtheria. This affects the soft palate, tonsils and pharyngeal area. A “leathery” grey/ yellow membrane is formed and is attached to the underlying tissue. Furthermore, the lymph glands become inflamed, swollen and tender. Infection may spread to the larynx leading to laryngeal diphtheria, which is characterised as a husky voice and a brassy cough. If there is airway obstruction it can further lead to a difficulty in breathing and a bluish discoloration.

Nasal diphtheria is a localised infection and you usually present with a low grade fever and nasal discharge.

Systemic spread of the exotoxins can lead to harmful effects primarily on the heart and nervous system.

Treatment

Diphtheria can be treated with both anti-toxin to help neutralise the exotoxins, and antibiotics to eradicate the bacteria. Antitoxin should be administered early on during the infection to prevent disease progression.

Prevention

It is important to get vaccinated to prevent diphtheria. Maintaining high vaccination levels in a population will lead to herd immunity and decreased transmission of the bacteria and thus the risk of disease. Moreover, improved sanitation, personal hygiene and a reduction in population crowding will prevent the spread of the bacteria. It is also advised that travellers avoid close contact with cattle and other farm animals as well as the consumption of raw dairy products in order to minimise the risk of infection.

Diphtheria vaccination information

Diphtheria toxoid vaccine is now only available as a combined vaccine. [Diphtheria (low- dose), Tetanus and Poliomyelitis Vaccine (Td/IPV- REVAXIS)].

Tetanus

Introduction

Tetanus is an acute disease caused by an exotoxin (tetanospasmin) which is produced by Clostridium tetani. This bacteria is heat sensitive and cannot survive in the presence of oxygen, however, it develops a terminal spore that is resistant to heat, antiseptics, phenol and other chemical agents. Tetanus is present worldwide and tetanus spores are present in soil and faeces of a number of animals.

The organism that causes tetanus, Clostridium tetani is present everywhere in the world. Since this disease is acquired through environmental exposure, it is one of the few vaccine- preventable diseases that is infectious but not contagious from humans to human contact. The incidence of tetanus in a country or area depends on the vaccine coverage. In resource- rich countries, like the United Kingdom, the vaccine coverage is high, hence the number of tetanus cases that are reported is very low.

Transmission

Tetanus spores are found in the intestine of most mammals including horses, sheeps, rats, chicken, dogs and cats. They are passed into the soil via faeces, making them present everywhere in the environment. The disease is acquired when material containing tetanus spores contaminates a wound of any severity. Wounds with a high risk of tetanus are those that show one or more of the following: deep puncture, contact with soil or manure and evidence of sepsis.

Signs and symptoms

The incubation period is usually 7 days, but ranges from 3 to 21 days. The further the injury site is from the central nervous system, generally the longer the incubation period. Individuals who have the shortest incubation period, there is a greater risk of fatality.

The signs and symptoms can be categorised according to the type of symptoms:

Local tetanus- This is a rare and milder form of the disease. It is characterised by a persistent contraction of muscles in the same area as the injury, and may persist for a few weeks before gradually subsiding.

Cephalic tetanus- This is a form of generalised tetanus, which occurs when the tetanus spores enter the middle ear, following a middle ear infection or a head injury.

Generalised tetanus- This accounts for about 80% of cases worldwide. After a period of discomfort, trismus ( also known as lockjaw) develops. This is characterised by spasms of the facial muscles and produces a grinning expression. Neck stiffness, difficulty swallowing and rigidity of the muscles, back and extremities follow.

Neonatal tetanus- This is the main form of tetanus in a resource- poor area. Illness begins 3 to 14 days after birth. Without specific treatment death occurs in more than 95% of cases. Death usually occurs secondary to infection of the umbilical stump if the end is cut with unsterilised instruments.

Prevention

Effective vaccination is available and all individuals should be immunised. Travellers should be up to date on their tetanus immunisation, be aware of the risk of accidents while travelling, and the importance of seeking urgent medical attention in the case of a penetrating wound.

Tetanus Vaccination Information

Tetanus toxoid vaccine is now only available as a combined vaccine. Travellers to areas where medical attention may not be accessible if a tetanus prone injury should occur and whose last dose of a tetanus- containing vaccine was more than 10 years previously, should receive a booster dose of Td/ IPV.

Poliomyelitis

Introduction

Poliomyelitis (polio) is an acute, potentially paralysing disease that can be prevented by the administration of a vaccine. It is caused by a polio virus, a small RNA virus of the genus Enterovirus. The risk of acquiring polio depends on factors such as standard of living, duration of stay, poor sanitation and food and water hygiene. Infected travellers excrete polio for a period of time and can even spread the virus to polio free countries. Until worldwide eradication is achieved, the risk to travellers acquiring the virus and the risk of polio being reintroduced to disease free regions remains.

Transmission

Polio is transmitted via the faecal- oral route. This can either be done by human to human contact or by exposure to faecally contaminated food or water.

Signs and symptoms

The incubation period for polio is between 3 to 21 days. The illness can be categorised according to the severity of symptoms:

Asymptomatic – 95% of all polio infections are asymptomatic

Minor, non-specific – This accounts for 4% to 8% of infections. Three syndromes are seen: Upper respiratory tract infection ( sore throat and fever), Gastrointestinal disturbances ( nausea, vomiting, abdominal pain, constipation and diarrhoea) and influenza-like symptoms.

Aseptic meningitis – Occurs in 1% to 2% of cases and is characterised by stiffness of the neck, back and/ or legs.

Flaccid paralysis – This occurs in less than 1% of all polio infections. Paralysis can affect single or multiple limbs and the respiratory muscles. About 50% of individuals with paralytic polio recover without paralysis, another 25% have mild permanent disability and 25% have permanent severe paralysis.

Prevention

Travellers should be advised to be vaccinated. They should also be advised to follow strict food and water hygiene as polio is transmitted via the faecal oral route. In addition to this, travellers should practice a high level of personal hygiene, i.e. hand washing, especially before eating. Swimming in chlorinated water is recommended and to avoid contact with water contaminated with sewage.

Availability of vaccine

Revaxis (dT/IPV) is the only vaccine licensed for use in adults.

If you want more information or require the vaccine for travel purposes, please book an appointment to speak to our trained pharmacist