Infections

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Questions Received:

  1. Why do muscles become painful when we have ‘flu?

  2. When my bladder infection was treated with antibiotics I had uncontrollable diarrhoea for 2 weeks - why?

  3. Can anyone give me the name of the disease caused by a parasite from a dogs feces, or the name of the parasite? It causes damage to a child.

  4. What are the effects of meningitis on the young child (0-5years old)?

  5. Can warts around the vagina be removed with "wart remover"?

  6. What are the preventions of infectious diseases?

  7. Why is fresh pineapple supposed to heal mouth ulcers? How much is needed daily?

  8. Could you list at least two diseases caused by Streptococcus faecalis?

  9. How does salmonella, clostridium and listeria affect the reproductive system?

Responses:

Why do muscles become painful when we have ‘flu?

2nd January 1999

Muscles become painful (myalgia) for a variety of reasons: for example, a build-up of lactic acid after vigorous activity can result in aching, painful muscles. In the case of the muscle pain commonly associated with influenza, there is evidence that it is a result of physical damage to muscle tissue caused either directly or indirectly by the viral infection (Bove, Hilton, Partin, and Farrell, 1983). Biopsies revealed localised degeneration of muscle fibres. The authors suggested that that destabilization of muscle cell membranes by the virus may play a role in producing myalgia. There is also some evidence that acute febrile infections including influenza may adversely affect neuromuscular transmission (Friman, Schiller, and Schwartz, 1977), and this may also contribute to the unpleasant myalgia of ‘flu.

References

When my bladder infection was treated with antibiotics I had uncontrollable diarrhoea for 2 weeks - why?

19th January 1999

Antibacterial drugs such as Trimethoprim and Amoxycillin are usually the first choice of drugs to be prescribed for the treatment of urinary tract infections. The organisms mostly commonly responsible for this type of infection are the same as those found in the bowel (e.g. Escherichia coli and Enterococcus faecalis). Therefore, in treating the infection many of the normal inhabitants of the intestines are killed too, resulting in gastro-intestinal disturbances and diarrhoea. Amoxycillin is particularly likely to produce this side effect. However, generally the diarrhoea subsides in a few days after the course of antibiotics has been completed as recolonisation and harmonisation of intestinal micro-organisms occurs.

It is always important to stress that the full course of antibiotics must be completed and that any unwanted effects should be reported to the prescribing doctor. Severe diarrhoea over longer periods can be debilitating - take care with your fluid balance and use reasonably isotonic drinks until the problem abates.

Bibliography

Can anyone give me the name of the disease caused by a parasite from a dogs feces, or the name of the parasite? It causes damage to a child.

10th February 1999

You are probably thinking of toxocariasis, more particularly the form known as ocular larva migrans (OLM). This is an eye disease that can cause blindness. It occurs when a parasitic roundworm that commonly lives in the intestines of dogs enters the eye where it produces inflammation and scarring of the retina. Children are particularly at risk when they play in areas where there are dog (or cat) faeces.

Although the dog is the main host for Toxocara canis (dog roundworm), cats and foxes can also be infected. The full lifecycle can be completed in 21 days (click on thumbnail for enlarged view):

Toxocara Canus - Lifecycle< Toxocara Canus - Lifecycle

 

 

 

 

 

 

 

 

 

In female dogs, the worm larvae migrate to skeletal muscles and become encysted, evading the immune system. The larvae remain dormant until pregnancy, when they become stimulated to finish their lifecycle in three ways:

It is virtually impossible to say that a bitch is 'worm larva free'. It is very difficult to remove encysted larvae with antihelminthics - the aim is to reduce the number of larvae with repeated treatments.

The worm eggs are sticky and very resistant to environmental factors. They can endure wet, cold, drying, and most disinfectants. They are likely to be ubiquitous in home environments where infected dogs are kept, and are present in house dust, dog fur, and carpets.

People can be infected by the dog roundworm, but the worms cannot complete their lifecycle in humans. Ingested eggs hatch into larvae and enter the blood stream, but the great majority are walled off and killed by the immune system without any clinical signs. 'Toxocara blindness' occurs very rarely when larvae migrate to the eye and the immune response results in damage to the light-sensitive retina.

To prevent toxocariasis infection, dogs should be routinely dosed with antihelminthics every 3 months. Hands should be washed between dog handling and eating, and young children allowed only limited handling of dogs, especially puppies. Puppies need to be wormed every 2 weeks from 3-4 weeks of age whatever the dam's worming history. The dog owner should be educated in the modes of infection and its prevention.

We are very grateful to Mr J.J. Darke BVetMed CertCHP MRCVS for the above information.

References

Useful information about prevention and treatment can be found at:

http://www.cdc.gov/ncidod/dpd/toxocar.htm

What are the effects of meningitis on the young child (0-5years old)?

14th April 1999

The term meningitis is applied to acute inflammation of the membranes covering the brain and spinal cord. Almost three-quarters of cases occur in children less than 5 years old. Meningitis is most commonly caused by bacterial or viral infection, and less commonly by fungi and protozoa. The causative factor generally gains entry through the lining of the respiratory system, as for example during a respiratory infection, although in babies entry may occur via the digestive tract or skin because of their incompletely developed immune system. Several types of bacteria can cause meningitis. In babies and young children, the organisms most frequently involved are Escherichia coli, Streptococcus agalactiae, and Haemophilus influenzae.

Bacterial meningitis is characterised by a sudden onset of fever, severe headache, painful rigidity of the neck, nausea, and vomiting. Convulsions are often seen in young children, and delerium or coma may occur. Meningitis can be fatal within hours or days, and those who survive the infection can be left with permanent brain damage and learning disabilities. A purulent exudate extends along the meningeal membranes, accompanied by haemorrhage and thrombosis. In meningococcal meningitis, the type that can become an epidemic, a skin rash becomes visible. This is produced by small haemorrhages from capillaries damaged by bacterial toxins. In other bacterial forms of meningitis a skin rash may not be present. There may also be damage to the adrenal glands, circulatory collapse, and shock.

Viral meningitis is clinically more benign and of short duration. Several viruses are capable of producing meningitis, for example herpes, polio, coxsackie, cytomegalovirus, measles, mumps, and influenza. The route of transmission of the infection is similar to that for bacteria, being from the respiratory or oral lining via the blood stream to the coverings of the brain. The signs and symptoms are similar to those for bacterial meningitis described above. The patients are treated supportively.

Meningitis is a medical emergency requiring prompt, accurate diagnosis and treatment. Most patients respond well to treatment and recover without permanent nervous system damage. Delay in treatment may result in permanent tissue damage or death.

Recommended Reading

Can warts around the vagina be removed with "wart remover"?

21st April 1999

It depends which "wart remover" is being referred to. Warts in the genital region are usually caused by viruses in the human papilloma virus family which has 60 or so members. Generally the warts remain benign, but some can be associated with later development of cancer of the cervix, vulva, vagina, and penis. In more than half of cases, the warts will disappear within one to two years without treatment. Detectable warts can be removed but often recur. Standard treatments include freezing with liquid nitrogen, cauterisation by electricity or laser light, application of a plant extract called podophyllin, or surgical removal. Human papilloma virus inhibits the immune system, and it has been found recently that the administration of interferon to enhance the immune response is therapeutic, although in some cases this treatment may have to be supported by diathermy of persistent warts (Zarcone et al, 1997).

Reference

What are the preventions of infectious diseases?

20th April 1999

First of all it is important to appreciate that in order to survive microorganisms require an optimum environment. Food, water, suitable temperature, the correct pH, and in most cases oxygen, are the conditions under which many microorganisms flourish. From this it can be appreciated that where these conditions exist reservoirs for infection can be found: on animals (including humans), insects, plants and in water, milk and food.

Prevention of infection falls broadly into three categories:

Public Health Measures

The provision of a safe, consistent uncontaminated water supply together with effective sewage disposal constitutes two very important measures which contribute to the health and wellbeing of a community. Comparisons can readily be made concerning the health status of citizens from a well developed nation against those who live in under developed areas of the world by viewing television news programmes and documentaries. Even in well developed countries public health measures can suddenly be severely disrupted by for example, overcrowding, civil unrest or war. Think for a moment about the threat to health that can exists when a person becomes a refugee. Particularly when such a person is deprived of: shelter, food and facilities for maintaining personal hygiene. Furthermore an indication of the health status of people living within a country can be gained by looking at that country's infant mortality rate. The infant mortality rate serves as a barometer, indicating the degree of ill health within a population.

Health Education

Many countries provide health education programmes for their citizens aimed at prevention of disease and enabling people to make informed choices about: diet, exercise, fitness, safe alcohol consumption and so on. Not only these but aspects directly related to the prevention of infection through: skin care, safe food handling, vaccination programmes and the prevention of sexually transmitted diseases, to name just a few. Schools, colleges and universities also support such initiatives by incorporating them into their culture for learning.

Vaccination

Ever since Edward Jenner in 1796 performed the first vaccination against smallpox by using the fluid which he obtained from cowpox blisters, vaccination has become a method whereby the incidence of major, frequently killer, diseases of the 19th. and early 20th. century - Tuberculosis, Measles, Diphtheria, Poliomyelitis, Rubella and Whooping Cough have been dramatically reduced. This form of immunity acquired by vaccination is known as active artificial immunity. Antibodies obtained from human or animal sources and administered prophylactically, or at the onset of a disease, confers passive artificial immunity - passive because the recipient has not been responsible for producing the antibodies. Other forms of immunity are natural active - acquired as result either having the disease or a sub-clinical infection, and natural passive - before birth, the mother's antibodies pass through the placenta and provide passive immunity for the unborn child. Also after birth, through the breast milk if the baby is breast fed.

Point of Interest: at the end of June 1999 the world's last batches of the smallpox virus are due to be destroyed. As recently as the sixties smallpox killed two million people a year. By 1980, the disease had been eradicated. Would destroying the remaining stocks of the virus protect the world? (Radio Times 8-14 May 1999. BBC Radio 4. pp115 'Killing the Killers' produced by Sarah Lewthwaite.)

External Body Defences

The skin and mucous membranes provide physical barriers which prevent pathogenic organisms entering the body. Although pathogenic organisms live on the skin and in hair follicles e.g. staphylococcus aureus and staphylococcus albus (skin commensals) they do not normally pass through the protective layers of the skin. Sweat and sebum production brings moisture onto the skin's surface and as such favours bacterial growth. However, these secretions are acidic and as such do not provide the appropriate environment for pathogens which favour an alkaline, whilst those which favour an acid environment thrive. Sweat and sebum also contains antibodies and lysozymes which help to inhibit bacterial colonisation on the skin's surface. The mucus membranes produce secretions which help to trap particles and move them away from those body cavities which they line. Tears, nasal secretions and tissue fluids contain lysozymes which destroy invading 'foreign' material.

The important role which the skin and mucus membranes have in protecting the cells and tissues inside the body can be appreciated. Small cuts, surgical wounds and burns expose the underlying tissues to pathogenic organisms and a full thickness large burn carries a particularly high risk.

Clinical Considerations

Good practice and high quality care delivery requires that doctors and nurses are educated about the prevention of infection and cross infection, the maintenance of asepsis, the avoidance of needle stick injuries, and infection control policies.

Why is fresh pineapple supposed to heal mouth ulcers? How much is needed daily?

1st January 2000

Fresh pineapple (from the Ananas comosus plant) is used as a traditional medicine throughout the tropics. The biological activity of pineapple comes from a family of enzymes called bromelain. Clinically, bromelain is primarily used to reduce inflammation and enhance healing (Alternative Medicine Review, 1998), so this would be the rationale behind the ingestion of fresh pineapple by people with mouth ulcers. The effects of bromelain appear to be dose-dependent, but at present there are no guidelines as to the optimum levels.

Bromelain is a family of at least four distinct cysteine proteinases (Rowan, Buttle, and Barrett, 1990). Bromelain extracted from the stem of the pineapple plant is somewhat different from the bromelain present in the fruit. Stem bromelain is a member of the papain superfamily of cysteine proteinases, but is not very closely related to any other known member of this group (Ritonja et al, 1989). Another cysteine proteinase called ananain has been isolated from pineapple stem bromelain (Rowan, Buttle, and Barrett, 1988).

The main applications of bromelain include inhibition of platelet aggregation, anti-inflammatory action, enhancement of fibrinolytic activity, interference with the growth of malignant cells, and skin debridement after burns (Taussig and Batkin, 1988; Lotz-Winter, 1990). Bromelain modulates the arachidonate cascade, enhances serum fibrinolytic activity and inhibits fibrinogen synthesis, lowers kininogen and bradykinin in serum and tissues, and has an influence on prostaglandin synthesis, thus acting as an anti-inflammatory substance (Lotz-Winter, 1990). In animal studies it was found that bromelain was absorbed unchanged into the bloodstream after ingestion and reached peak levels about one hour after ingestion (White et al, 1988; Lotz-Winter, 1990).

It is worth noting that some people develop allergic reactions to bromelain when they work in places where there are significant quantities in use - for example in the pharmaceutical industry, food production, and diagnostic laboratories. However, sensitisation usually occurs due to inhalation and not by ingestion (Gailhofer et al, 1988), so this is unlikely to be a problem when fresh pineapple is used.

References

Could you list at least two diseases caused by Streptococcus faecalis?

26th January 2000

Streptococcus faecalis is also called Enterococcus faecalis, which may be worth knowing if you are searching for information on this subject. It may be the causative organism in cases of endocarditis, urinary tract infection, and bacteraemia. It can also cause sepsis within the biliary tract after a liver transplant (Burkitt et al, 1996 pp 15-16). Streptococcus faecalis is also called Enterococcus faecalis, which may be worth knowing if you are searching for information on this subject. It may be the causative organism in cases of endocarditis, urinary tract infection, and bacteraemia. It can also cause sepsis within the biliary tract after a liver transplant (Burkitt et al, 1996 pp 15-16). Streptococcus faecalis is also called Enterococcus faecalis, which may be worth knowing if you are searching for information on this subject. It may be the causative organism in cases of endocarditis, urinary tract infection, and bacteraemia. It can also cause sepsis within the biliary tract after a liver transplant (Burkitt et al, 1996 pp 15-16). Streptococcus faecalis is also called Enterococcus faecalis, which may be worth knowing if you are searching for information on this subject. It may be the causative organism in cases of endocarditis, urinary tract infection, and bacteraemia.

It can also cause sepsis within the biliary tract after a liver transplant (Burkitt et al, 1996 pp 15-16). Streptococcus faecalis is also called Enterococcus faecalis, which may be worth knowing if you are searching for information on this subject. It may be the causative organism in cases of endocarditis, urinary tract infection, and bacteraemia. It can also cause sepsis within the biliary tract after a liver transplant (Burkitt et al, 1996 pp 15-16). Streptococcus faecalis is also called Enterococcus faecalis, which may be worth knowing if you are searching for information on this subject. It may be the causative organism in cases of endocarditis, urinary tract infection, and bacteraemia. It can also cause sepsis within the biliary tract after a liver transplant (Burkitt et al, 1996 pp 15-16).

Streptococcus faecalis is a Gram-positive bacterium whose normal habitat is the gut of humans and most animals. Most infections are endogenously acquired but cross infection may occur in hospitalised patients (Mims et al, 1998). The urinary tract is the most common site of infection but Streptococcus faecalis may not be the only organism responsible. Other enteral organisms such as Escherichia coli, Proteus spp., and Pseudomonas are also capable of invading the urinary tract (Burkitt et al, 1996 pp 437-440). Streptococcus faecalis is sensitive to Ampicillin/amoxycillin. Aminoglycosides (e.g. Gentamicin) may also be given in combination with penicillin (British National Formulary, 1999).

Antibiotic Policies are now in operation in most hospitals within the UK, and the prescription of antibiotics to treat infections caused by organisms such as Streptococcus faecalis is normally achieved through liaison with a consultant microbiologist.

References

How does salmonella, clostridium and listeria affect the reproductive system?

19th June 2000

The Salmonella species is a family of approximately 2000 variants, most of which cause gastroenteritis. If the bacteria enter the bloodstream, they can produce perineal and pelvic abscesses which may affect the reproductive system.

The Clostridium species includes C. botulinum and C. tetani. They are found in the soil, for example, and generally gain entry to the body through damaged tissues such as wounds and ulcers. Uterine infections with C. perfringens can occur after incomplete abortions using non-sterile procedures, and cause high mortality.

Listeria is distributed in soil and water and by domestic and wild animals. It is usually acquired by eating contaminated food. Most healthy humans are resistant to Listeria, but when listeriosis occurs in pregnant women the fetus may become infected via the placenta. This can result in miscarriage or stillbirth. If the baby survives birth it may develop sepsis and meningitis. Listeria is distributed in soil and water and by domestic and wild animals. It is usually acquired by eating contaminated food. Most healthy humans are resistant to Listeria, but when listeriosis occurs in pregnant women the fetus may become infected via the placenta. This can result in miscarriage or stillbirth. If the baby survives birth it may develop sepsis and meningitis. Listeria is distributed in soil and water and by domestic and wild animals. It is usually acquired by eating contaminated food. Most healthy humans are resistant to Listeria, but when listeriosis occurs in pregnant women the fetus may become infected via the placenta. This can result in miscarriage or stillbirth. If the baby survives birth it may develop sepsis and meningitis. Listeria is distributed in soil and water and by domestic and wild animals. It is usually acquired by eating contaminated food. Most healthy humans are resistant to Listeria, but when listeriosis occurs in pregnant women the fetus may become infected via the placenta. This can result in miscarriage or stillbirth. If the baby survives birth it may develop sepsis and meningitis. Listeria is distributed in soil and water and by domestic and wild animals. It is usually acquired by eating contaminated food. Most healthy humans are resistant to Listeria, but when listeriosis occurs in pregnant women the fetus may become infected via the placenta. This can result in miscarriage or stillbirth. If the baby survives birth it may develop sepsis and meningitis. Listeria is distributed in soil and water and by domestic and wild animals. It is usually acquired by eating contaminated food. Most healthy humans are resistant to Listeria, but when listeriosis occurs in pregnant women the fetus may become infected via the placenta. This can result in miscarriage or stillbirth. If the baby survives birth it may develop sepsis and meningitis.

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