3.1.3 Bacterial diseases

• Disease: Salmonella

  Symptoms:

  ● Fever, abdominal cramps, vomiting & diarrhoea

  ● Due to toxins (poisons) secreted by bacteria

  How is it spread?

  ● Bacteria ingested in food (eg. chicken)

  ● Or on food prepared in unhygienic conditions

  How can spread be reduced or prevented?

  ● Poultry eg. chickens vaccinated

  ○ So fewer bacteria in chicken / eggs

  ○ So fewer bacteria ingested by humans

  ● Wash hands before preparing food / disinfect surfaces
• Disease: Gonorrhoea

  Symptoms:

  ● Thick yellow / green discharge from vagina or penis

  ● Pain when urinating

  How is it spread?

  ● Sexually transmitted disease (STD) so spread by sexual contact

  How can spread be reduced or prevented?

  ● Antibiotics → was easily treated with penicillin until many resistant strains of gonorrhoea appeared

  ● Use of barrier methods of contraception eg. condoms
• why is this statement wrong?

  “Humans are vaccinated against Salmonella.”

  Poultry are vaccinated, not humans.
• why is this statement wrong?

  “Chickens get Salmonella food poisoning.”

  Chickens can carry the Salmonella bacteria, but it only causes food poisoning (the disease) in humans.
• Suggest why the number of cases of Salmonella food poisoning is usually higher in summer than in winter. (1)

  ● Warmer weather so bacteria reproduce faster

  ● Food not cooked properly on barbeques
• Other than vaccination, suggest how farmers could prevent the transmission of Salmonella from chickens to humans. (2)

  ● Give chickens antibiotics

  ● Don’t sell infected chickens / eggs

  ● Keep infected chickens isolated

  ● Slaughter infected chickens
• Suggest reasons why the number of cases of Salmonella food poisoning has decreased. (2)

  ● Improved hygiene for food preparation

  ● Vaccination of poultry