INFECTIOUS DISEASES

See also Childhood immunisation, Respiratory tract infections, Sexually transmitted infections, Travel health

Vaccination

The UK programme of routine childhood immunisations protects against many infectious diseases (see section on ‘Child health’). Other vaccinations are offered where appropriate, e.g. influenza vaccine to the over-65s, hepatitis A vaccine to travellers to high-risk areas.

Notifiable diseases

Notification of infectious diseases (NOIDs) is required for certain infections under the Public Health (Control of Diseases) Act 1984 and Public Health (Infectious Diseases) Regulations 1988. Notification is made to the local authority’s Medical Officer for Environmental Health (who provides the necessary forms). Notification allows developing outbreaks and epidemics of infectious disease to be identified. Rapid reporting is the prime concern – an incorrect diagnosis can always be changed or cancelled. 

To see a larger version click here

Incubation periods

 

To see a larger version click here

 

To see a larger version click here

Chlamydia trachomatis

Most common bacterial STI in the UK. Perinatal transmission may result in neonatal conjunctivitis. Many cases remain undiagnosed.

Women: 80% asymptomatic; may be cervicitis, mucopurulent discharge, cervical bleeding, postcoital or intermenstrual bleeding, lower abdominal pain, dysuria. Untreated infection can cause chronic pelvic pain and lead to pelvic inflammatory disease (PID), ectopic pregnancy and infertility.

Men: 50% asymptomatic; may be urethral discharge and/or dysuria; testicular/epididymal pain; anal/rectal discomfort (proctitis). Complications are rarer but can include epididymitis (pain and swelling around the testicles) and Reiter's syndrome (arthritis).

National Chlamydia Screening Programme (NCSP): a control and prevention programme targeted at the highest risk group for chlamydia infection in England, young people under 25 who are sexually active. One in 10 people under 25 years who have had a test are infected.

COVID-19/SARS-CoV-2

See detailed entry under CORONAVIRUS | COVID-19

Creutzfeldt-Jacob disease (CJD)

Rare, fatal disease causing degeneration of nervous tissue. A variant form, vCJD, results from exposure to the agent that causes bovine spongiform encephalopathy (BSE) in cattle.

Diphtheria

• Notifiable disease

Acute bacterial infection with Corynebacteria diphtheriae. Affects upper respiratory tract and occasionally skin. An inflammatory exudate forms a greyish membrane in the respiratory tract. Spread is by droplets and contact with articles soiled by an infected person. Vaccine is routinely given in childhood and to school leavers, combined with tetanus and polio. The combined vaccine is also used in adults.

 

Gonorrhoea

Usually sexually transmitted in adults. Perinatal transmission results in eye infection, which is a notifiable condition. In older children, suspect sexual abuse.

Symptoms Men: generally uretheral infection within 10 days. Usually mucoid purulent discharge or dysuria, but up to 10% asymptomatic. Rectal infection usually asymptomatic but can cause rectal/anal pain/discharge.

Women: possible cervical infection, low abdominal infection, pelvic pain, often asymptomatic. Mucoid purulent vaginal discharge in 50%.

Both sexes: pharyngeal infection with exudates (usually asymptomatic).

Hand, foot and mouth disease

Generally mild illness affecting mostly children under 10 years; usually clears within 1 week. Caused by the coxsackie A virus or sometimes coxsackie B and enterovirus 71. Very occasionally meningoencephalitis or myocarditis may occur. Some evidence that may rarely be harmful in pregnancy. Presents with raised temperature, sore throat, and spots in the mouth that turn to ulcers, then spots on hands and feet, occasionally buttocks, legs and genitals. Good hygiene measures reduce spread of virus.

Hepatitis

• Notifiable

The hepatitis viruses A, B, C, D and E cause acute hepatitis. Hepatitis B and, particularly, C, can cause chronic infection that can lead to cirrhosis, liver failure, and liver cancer. All types of viral hepatitis are notifiable diseases in UK. Practices will have a policy for vaccinations against hepatitis A and B. Acute infection may present with:

• nausea and vomiting
• myalgia
• fatigue/malaise
• right upper quadrant pain
• change in sense of smell or taste
• coryza
• photophobia
• headache.

Diarrhoea (with pale stools) and dark urine may also be present. However, often no signs unless jaundice develops, when hepatomegaly, splenomegaly and lymphadenopathy may occur.

Hepatitis A Previously a common childhood infection in the UK but now unusual. May occur in outbreaks in institutions, and is common in travellers. Infection confers immunity. Spread normally by the faecal-oral route (ingestion of food or drink contaminated by infected stool) but occasionally through blood. Usually self-limiting (rarely fulminant); there is no carrier state, and chronic liver disease does not occur. HepA vaccine can protect people at high risk, eg, those who have been in contact with an infected person, travellers to countries where the infection is common, and injecting drug users.

Hepatitis B Early symptoms flu-like; infection can lead to liver disease and liver cancer. Hepatitis B is 10-100 times more infectious than HIV. Transmitted by contact with infected blood or body fluids, e.g. by:

• sharing or use of contaminated equipment during injecting drug use
• vertical transmission (mother to baby) from an infectious mother to her unborn child
• sexual transmission
• receipt of infectious blood (via transfusion) or infectious blood products (e.g. clotting factors)
• needlestick or other sharps injuries (in particular those sustained by healthcare workers)
• tattooing and body piercing.

HepB vaccination:

• should be given to all individuals at risk, including health professionals.
• is usually provided free (on the NHS) to people in a high-risk group.

For guidance on when HepB for travel can be provided as an NHS service or privately, see https://www.bma.org.uk/advice-and-support/gp-practices

Hepatitis C Often asymptomatic initially; 15-20% clear their infection within 2-6 months. Of those with chronic infection, some remain well but many develop mild to moderate liver damage (with or without symptoms); of these, 20% progress to cirrhosis over 20–30 years. Excessive alcohol consumption increases risk of severe liver complications. HepC is blood borne and most often acquired through injecting drug use; also by sharing razors or toothbrushes or during body piercing (eg, tattooing, acupuncture) with non-sterile needles. Was also spread by blood transfusions before September 1992, when screening for hepatitis C was brought in. There is no vaccine. Increasingly effective drug treatment (not suitable for everyone, lasts 6 or 12 months) can clear the virus in c. 50%. Around 100,000 people in England are thought to have undiagnosed HepC; DH runs awareness campaigns to promote diagnosis and treatment.

Hepatitis D An important cause of acute and severe chronic liver damage in some parts of the world (Mediterranean, parts of Eastern Europe, Middle East, Africa, and South America). Occurs only in people infected with HepB.

Hepatitis E Uncommon in the UK, but common in Asia, Africa and Central America, particularly where sanitation is poor. Disease is usually mild but rarely can be fatal, particularly in pregnant women. Transmission and clinical features similar to HepA. See also Travel health, Sexual health

Herpes simplex virus (HSV) infection

Herpes Labialis (cold sores) - localised collection of blisters with a red base, usually on or around the lips, that develop into crusts and disappear without scarring. Manifestation of a recurring infection with the herpes simplex virus (HSV), usually but not exclusively HSV1. Lesions are contagious until dried out

Genital herpes is almost exclusively a sexually transmitted infection, generally caused by HSV2, although the prevalence of genital HSV-1 is increasing. Most transmission occurs via sexual contact with an individual who may be asymptomatic but is still shedding the virus. There is some evidence that genital HSV increases the risk of acquiring (and transmitting) HIV infection.

Genital herpes in pregnancy – in early pregnancy is associated with an increased risk of spontaneous abortion, fetal growth restriction, preterm labour and congenital herpes. In later pregnancy, genital herpes caries an increased risk of neonatal infection.

Herpes zoster virus infection

Chickenpox Highly contagious infection with the varicella-zoster herpesvirus, usually affecting children. An attack gives lifelong immunity, but the virus remains dormant in nerves and in later life may cause shingles (see below) Causes crops of itchy vesicles, typically starting on the back. Spread by direct contact or the respiratory route, via droplets. Seek advice if chickenpox exposure or infection occurs during pregnancy or if neonatal infection.

Shingles Rash caused by reactivation of the dormant chickenpox (varicella zoster) virus, often many years after original infection. Shingles is not infectious, but a person who has never had chickenpox may become infected with chickenpox from a person with shingles. Reactivation of the latent virus leads to the clinical manifestations of shingles, mostly in older people or those who are immunocompromised. The risk and severity of shingles increases with age. Following the rash (often intensely painful and itchy, and lasting from 2 - 4 weeks), persistent pain known as post herpetic neuralgia can develop. Routine vaccination against shingles is now offered to people aged 70 - 80. 

Human immunodeficiency virus (HIV) infection/AIDS

HIV is a retrovirus that infects T helper lymphocytes, cells that co-ordinate the actions of other immune system cells and carry the CD4 receptor. Over time the patient’s CD4 count declines, susceptibility to infections increases, symptoms develop, and become more severe until a diagnosis of AIDS (acquired immune deficiency syndrome) is made.

See entry for Human Immunodeficiency Virus (HIV) and AIDS

Infectious mononucleosis (glandular fever)

Mildly infectious disease caused by the Epstein-Barr virus (EBV). Consider in teenager or young adult with sore throat for more than 1 week. Also malaise, fatigue, cervical lymphadenopathy, headache, splenomegaly, maculopapular rash and loss of appetite. Spread by close contact.

Influenza

Highly contagious acute viral infection of the upper respiratory tract. Onset is sudden, symptoms include headache, myalgia, fever and cough. Spread is by droplet, person-to-person contact or contact with contaminated items, e.g. door handles. May predispose to secondary bacterial infection of the upper and lower respiratory tract. Most recover in 1–2 weeks without complications but ‘flu’ can cause serious illness and death, especially in very young, elderly or infirm. Influenza occurs most often in winter and usually peaks December–March in the northern hemisphere. Every 2–3 years epidemics occur, and mortality may be high.

Measles

• Notifiable

Highly contagious acute viral illness (RNA paramyxovirus), usually affecting children. Generally presents with fever, cough, irritability, coryza, conjunctivitis, Koplick spots inside cheeks. Dark red macular or maculopapular rash behind ears, spreading to face and trunk. Spread is by respiratory droplets. A vaccine is given as part of the combined MMR (measles, mumps and rubella) vaccine (see Green Book)

Meningitis

• Notifiable

Inflammation of the meninges, the protective membranes covering the brain and spinal cord. May be viral or bacterial.

Viral meningitis can cause a person to feel very unwell but they usually make a full recovery within 2 weeks; treatment is rest and analgesics. Most viruses that cause meningitis are enteroviruses that are normally harmless, and passed on as a result of poor hygiene.

Bacterial meningitis can kill a healthy person of any age within 4 hours of first symptoms, or cause permanent disability (loss of limbs, blindness, deafness, brain damage).

Hib meningitis is caused by Haemophilus influenzae type b; most common in babies and children. 

Meningococcal meningitis is caused by the meningococcus Neisseria meningitides; most prevalent in children

Pneumococcal meningitis, second most common form of bacterial meningitis in UK, is caused by Streptococcus pneumoniae, which can also cause ear infections and pneumonia. Less common than meningococcal meningitis, but much more life threatening. Both types of bacteria can cause, separately or together:

• meningitis (infection of the meninges/spinal cord) and
• septicaemia (blood poisoning).

Septicaemia is more dangerous, causing blood vessels to haemorrhage.

Symptoms Some of the symptoms for meningitis and meningococcal septicaemia are the same, others differ. Not everyone gets them all, and they can develop in any order. In the early stages both diseases can appear flu-like.

Meningococcal septicaemia

• fever
• rigors
• severe muscle and joint aches
• isolated, severe limb pain
• gastrointestinal symptoms: abdominal pain, vomiting, diarrhoea.
• weakness, may be profound.
• rash: parents may not recognise the purpura/bruises or petechiae of septicaemia as a ‘rash’. The spots do not fade under pressure, i.e., they remain visible through the side of a clear drinking glass pressed firmly against the skin.

Meningitis 

• fever
• headache
• vomiting
• drowsiness/confusion
• fits
• photophobia
• neck stiffness.

• Encourage parents to trust their instincts, and seek medical advice again if child’s condition deteriorates
• Give information about symptoms of serious illness, including how to identify a non-blanching rash
• Give a specific follow-up time
• Advise how to liaise directly with other health professional if concerned.

Vaccination Childhood vaccination protects against meningitis C, pneumoccoccal meningitis and Hib meningitis. A new vaccine against meningitis B is due to be introduced later in 2014 which is thought to offer around 88% protection against this, the most common form of meningitis, which affects around 1,200 people a year – both adults, babies and young children – and which has a high risk of limb amputations, brain injury and death. Uptake levels of MenC vaccine since introduction in 1999 is close to 90%; cases have reduced by 90% in under-20-year-olds, the target group. Young adults aged 20–24 remain at risk and all first-year college and university students who have not already received the Men C vaccine should do so, ideally before starting their course.

• Notifiable

An acute viral illness that causes swelling of the parotid glands (unilateral or bilateral); can cause permanent unilateral deafness at any age. Spread is by contact with saliva or droplets from the saliva of an infected person. Vaccine given in childhood as part of the triple MMR (mumps, measles, rubella) vaccine

Pertussis (whooping cough)

• Notifiable

Highly infectious bacterial disease caused by Bordetella pertussis. Spread is by droplets. Irritating cough develops into coughing fits. In young infants, the characteristic 'whoop' may never develop and coughing spasms may be followed by periods of apnoea. Vaccine routinely given in childhood.

Polio (poliomyelitis)

An acute illness occurring when polio virus invades the gastrointestinal tract. Spread is faecal-oral or by droplets. Paralysis can result if nervous system is affected. Post-polio syndrome may occur many years later, with worsening of neurological deficit.

• Notifiable

Vaccination against polio is now part of the routine childhood programme, but people born before 1958 may not have been immunised. The Global Polio Eradication Initiative was launched in 1988 with the objective of vaccinating ‘every last child’; in May 2014 the World Health Organization declared the international spread of wild poliovirus ‘a public health emergency of international concern.’ The virus is currently circulating in Cameroon, Pakistan, Syria, Afghanistan, Equatorial Guinea, Ethiopia, Iraq, Israel, Nigeria and Somalia.

Rabies

• Notifiable

Almost always fatal encephalitis caused by the rabies virus, acquired from the saliva of an infected animal. Infection is usually via a bite, but scratches or licks to broken skin or mucous membranes are equally risky. May enter the UK via unvaccinated pets. There is no treatment. Consider pre-exposure immunisation for people visiting areas where rabies is endemic.

Advice if bitten in a country where rabies is present

• Wash site with soap and water
• Seek immediate medical advice/begin post-exposure immunisation
• Consider tetanus booster and antibiotics

Rubella (German measles)

• Notifiable

Mild viral infection that is trivial in children, more severe in adults. One attack confers immunity. Maternal rubella infection in early weeks of pregnancy causes fetal damage (commonly multiple defects) in up to 90% of infants (congenital rubella syndrome). Generally presents with macular facial rash that spreads to trunk and limbs, fading within 4 days; also cervical lymphadenopathy, fever and myalgia. Spread is by airborne droplets. Vaccine given in childhood as part of the triple MMR (measles, mumps and rubella) vaccine.

Slapped cheek syndrome (erythema infectiosum, fifth disease)

Viral infection (parvovirus B19) that may be asymptomatic but often presents with mild fever, sore throat and gastrointestinal upset; a bright erythematous rash (resembling slapped cheeks) may develop on the face, and may spread over the body, lasting 1-3 weeks. Usually affects school-aged children. In pregnancy, there are associated dangers.

Syphilis

Infection with bacteria-like spirochete Treponema pallidum. Transmitted during sexual intercourse and from an infected pregnant woman across the placenta to a developing baby. Symptoms Primary: generally presents as a painless and indurated ulcer (chancre) discharging clear serum and regional lymphadenopathy, 9–90 days after exposure. Secondary: multisystem involement with polymorphic rash (non–itchy). Tertiary: 2-20 years after initial infection: granulomas in connective tissue Quaternary: cardiovascular or neurological complications

Tuberculosis

• Notifiable

Chronic infectious disease caused by Mycobacterium tuberculosis. Leading cause of death among curable infectious diseases, and a massive problem worldwide; WHO declared TB a global emergency in 1993. In England cases fell progressively until the mid-1980s but started to rise again in the early 1990s. In 2012, there were 8,751 cases of TB reported in the UK (13.9 per 100,000), where most cases occur in large cities, especially London; the London region accounted for 40% (44.8 per 100,000). Groups at risk include: alcoholics, undernourished, ethnic minority communities and the HIV population. TB and HIV/AIDS co-infection leads to substantial morbidity and mortality. Initial infection is by droplets, spread being usually by coughs or sneezes of an infected person, but TB is not highly contagious. TB is curable with a course of specific antibiotics taken for at least 6 months. The most important part of controlling TB is identifying and treating those who already have the disease, to shorten their infection and to stop it being passed on to others. Vaccination is with a live attenuated strain of Mycobacterium bovis (BCG vaccination) and is targeted at vulnerable groups.

TETANUS (lockjaw)

• Notifiable

Infection with bacterium Clostridium tetani, an anaerobic, spore-forming bacillus found in dust, soil, vegetation and GI tracts of humans and animals. Tetanus toxin causes generalised or localised tonic spasticity with or without tonic convulsions. Suspect in any patient who develops muscle stiffness or spasm several says after incurring a skin wound or burn.

Tetanus-prone injuries

• Any burn or wound sustained >6h before surgical treatment of that wound
• Any burn or wound that:

          - has a substantial amount of dead tissue within it

          - is a puncture-type wound

          - has been in contact with soil or manure likely to harbour tetanus organisms

          - is clinically infected.

Vaccine is routinely given in childhood. Primary immunisation is three doses of a tetanus-containing combined vaccine at recommended intervals; booster doses (using a combined vaccine): first ideally 3 years after completion of primary course, second ideally 10 years after the first booster dose. In most circumstances a total of five doses of vaccine at the appropriate intervals is considered to give satisfactory long-term protection (see Green Book).