Communicable diseases

Communicable diseases are those that are transmissible from one person, or animal, to another. The disease may spread directly, via another species (vector) or via the environment. The spread of disease in the community is determined by environmental and social conditions that favour the infectious agent, and the relative immunity of the population.

Public Health England provides local health protection services and lead the public health response to communicable disease outbreaks and emergencies that need specialist expertise. They give local government, especially the Director of Public Health access to specialised advice and support and help to improve the health and wellbeing of their population.

This chapter considers communicable diseases as a broad topic. For more information on sexually transmitted infections please refer to the Sexual Health chapter, and for more information on vaccine preventable diseases please refer to the Immunisation and childhood immunisation chapters and to the excess winter deaths and flu chapter.

What do we know?

The rate of diagnosis of tuberculosis in the UK is higher than most other Western European countries and more than four times as high as the USA. Following a decline during most of the 20th century, the incidence of TB has been increasing since the 1980s and has remained at relatively high levels since 2005.The majority of TB cases are curable, however, resistance to drugs is becoming a significant challenge.

Nationally, three quarters of TB cases are born outside of the UK. It is thought that most cases of TB disease in the UK are likely to originate from an activation of latent TB (bacteria that are ‘asleep’ in the body). Around 1 in 4 new entrants in the UK have latent TB and 1 in 10 infections will be ‘reactivated’, usually 2-5 years after arrival. There is a strong association between TB and social deprivation, with 70% of cases occurring among residents of the 40% most deprived communities in England.

 (Source: Tuberculosis in the UK 2015 Report and Collaborative TB strategy for England).

Gastrointestinal Infections affect 1 in 5 people each year. Symptoms include (but are not limited to) diarrhoea and vomiting. Norovirus (commonly known as winter vomiting bug) is a highly infectious viral cause of gastroenteritis, therefore commonly responsible for outbreaks, particularly in enclosed environments such as hospitals, schools and nursing homes. Rotavirus is the most common cause of gastroenteritis in infants and very young children. Almost every child will have had an infection by the age of 5. Campylobacter is the most commonly isolated bacterial cause of gastroenteritis (usually cases of food poisoning) reported to Public Heath England.

Washing hands is vital for prevention of gastrointestinal infections. Hand-washing reduces risk of developing gastroenteritis by 50%.

Blood-borne viruses (BBVs) are viruses that some people carry in their blood and include Hepatitis viruses and HIV. Hepatitis C infection is often asymptomatic, and therefore is thought to be undiagnosed in many. This is particularly important as symptoms may not appear until the liver is severely damaged. Almost 90% of hepatitis C cases in the UK occur in people who inject drugs or have injected them in the past.

(Source: Hepatitis C in the UK 2015 and NHS Choices Hepatitis C)

Infections that acquired within a healthcare setting are known as healthcare associated infections (HCAIs) or nosocomial infections. NHS organisations both in primary and secondary care have made some progress with reducing rates of healthcare associated infections.

Facts, figures, trends

Tuberculosis: There were 221 cases of Tuberculosis (TB) among Slough residents between 2012 and 2014, giving an incidence rate of 51.5 per 100,000 population. Though still significantly higher than the national average, this was a slight improvement on previous figures (Figure 1).

Over 95% of TB cases in Slough had completed a full course of treatment by 12 months in 2013, Slough was in the top 10% of local authorities in England in terms of treatment completion. Less than 2% of drug-resistant TB cases died during follow-up which is within the top 10-50% of local authorities in England.

Figure 1: Incidence of TB in Slough from 2004-06 to 2012-14

Figure 1

Figure 2: Proportion of cases completing 12 months of treatment

Figure 2

Gastrointestinal Infections: there were 24 cases of food poisoning reported to Public Health England in Slough in 2014, this is higher than the two reports in the previous year, but similar to rates in neighbouring boroughs.

Blood-borne Viruses (BBVs): In 2012, there were 65 hepatitis B virus cases (acute and chronic) and significantly higher than in the previous year (51 in 2011). The rate of early death from hepatitis C related liver disease is slowly increasing (0.49 per 100,000 over 2012-14) though remains similar to the national average.

Healthcare associated infections (HCAI): rates of C.difficile infection were reduced from 15.3 per 100,000 in 2013/14 to 12.5 per 100,000 in 2014/15. Similarly, rates of MRSA infections in the blood reduced from 2.1 per 100,000 in 2013/14 to 0.7 per 100,000 in 2014/15.

Mortality from infectious and parasitic diseases shows the total number of deaths in a population from those diseases during a given time period. As the number of deaths in an area will be heavily influenced by the age and gender of the population, figures have been adjusted to take into account these factors. Figure 3 shows that this rate was higher in Slough between 2011 and 2013 than the national average, however, it is improving.

Figure 3: Mortality rate from communicable disease in Slough 2001-03 to 2011-13

Figure 3

National and local strategies (current best practices)

There are number of national and local strategies to control and prevent various communicable diseases. Some important ones to mention are:

What is this telling us?

Overall, the number of people either at-risk or suffering from communicable diseases in Slough is high. The number of TB cases is very high, however, the TB services are good, as evidenced by high TB completion rate at 12 months. HIV prevalence is high and late diagnosis of HIV is still an issue (discussed in the sexual health chapter).

What are the key inequalities, unmet needs/service gaps?

  • Wide variation in BBV screening and Hepatitis B vaccination uptake among high-risk groups.
  • HIV screening, offer / uptake of HIV testing among high-risk groups are patchy.
  • No standard protocol or screening for TB in primary care.

Recommendations for consideration by other key organisations

  • Implement HIV screening / testing as per national guidelines.
  • Improve early detection of HIV and reduce the number of late HIV diagnosis and to reduce risk of morbidity and mortality associated with late diagnosis.
  • Implement the primary-care based TB screening programme in partnership with Local Authorities (for example: Housing, benefit etc.) and other agencies.
  • Sustain and improve the good quality TB services.
  • Improve BBV screening and Hep B vaccination service among high-risk groups.
  • Agencies to work with PHE to control / prevention of communicable diseases.

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