Zika infection: just the beginning?

ศาสตร์เกษตรดินปุ๋ย : ขอบคุณแหล่งข้อมูล : หนังสือพิมพ์ The Nation



Declared earlier this month by the World Health Organisation (WHO) as a public health emergency of international concern, the Zika virus infection has been the subject of near-hysterical headlines because of its rapid spread and for its suspected complications in newborns.

So what is known today about this disease?

Zika is an arbovirus, which means a virus transmitted by a mosquito. It belongs to the flavivirus family that includes the dengue, chikungunya and Japanese Encephalitis viruses. Zika is not a new virus. It was first identified in the Zika forest in Uganda in 1947, hence the name, and was responsible for outbreaks in Micronesia in 2007 and in French Polynesia in 2013. Sexual contamination of the Zika virus has recently also been demonstrated in the USA but this route of transmission is likely to remain negligible in comparison with mosquito bites.

Right now, Zika outbreaks are mainly hitting Latin American countries and some West-Indies islands. However as the vector is the ubiquitous mosquito from the Aedes genus, there is a significant likelihood that the virus will spread too in other tropical countries in Asia (including theMekong countries), Africa as well as the southern parts of the western hemisphere due to the new expansion of Aedes in these latter regions. To date, only a few cases have been reported in Thailand over the last few years. Contrary to the Anopheles mosquitoes that transmit malaria, the Aedes mosquitoes are particularly well adapted to urban areas.

In about 80 per cent of the cases, a Zika infection is essentially a benign illness inducing no or mild symptoms. When symptoms do occur, the patient may present a skin rash, mild headache, low-grade fever, muscular and joint pains, fatigue and red eyes (conjunctivitis) for a few days. Some of these symptoms may be suggestive of other tropical diseases, in particular dengue.

The diagnosis is confirmed by specific tests to identify or isolate the virus in the blood.

The main issues with Zika infection are the suspected neurological complications that include the possible newborn defect named microcephaly -a congenital brain condition where a baby’s head is much smaller than average size – and the Guillain-Barre syndrome a progressive and potentially severe neurological disorder in adults that may be – although rarely – irreversible. Despite the 20-fold increase in microcephaly in some Brazilian states and the proven maternal-foetal transmission of Zika during pregnancy, the association of Zika with the birth defect complications is based on epidemiological data and not yet formally established. However, some public health authorities have already issued various recommendations for pregnant women. These include specific Zika screening and/or avoid travelling in endemic Zika areas and/or considering postponing planned pregnancy and/or strictly following advice to prevent mosquito bites.

There is no antiviral medication to treat Zika virus infection and no vaccine to prevent it. In symptomatic cases, the treatment is limited to relieving the intensity of fever and joint pains. Aspirin should be avoided due to the risk of haemorrhage induced by possible concomitant dengue infection.

The Guillain-Barre syndrome complication is treated with supportive care because there is also no cure for this disorder. However most patients eventually recover from this syndrome. On the other hand and depending on its severity, the microcephaly complication usually leads to lifelong developmental and neurological problems that can be life-threatening.

The basic prevention of Zika infection, like other arbovirus diseases, is then to avoid mosquitoes bites as much as possible. For children, leisure or playgrounds infested by insects should be avoided at anytime of the day. Long sleeved clothing should be worn. The use of repellent, preferably one containing DEET (N.N-diethyl-3-methylbenzamide), in regular applications every two to four hours, is recommended as well as the use of mosquito nets. Aerosol insecticide may occasionally be sprayed in the house.

Despite huge challenges, global prevention nevertheless starts from implementing serious public health measures to reduce standing water in the urban environment, which tends to lead to a significant reduction in the mosquito population.

DR GERARD LALANDE is managing director of CEO-Health, |which provides medical referrals for expatriates and customised |executive medical check-ups in Thailand. He can be contacted at gerard.lalande@ceo-health.com.

The fight against thalassaemia

ศาสตร์เกษตรดินปุ๋ย : ขอบคุณแหล่งข้อมูล : หนังสือพิมพ์ The Nation



A genetic or inherited blood disorder that affects both men and women and can be passed from parents to children through genes, thalassaemia is a blood disorder in which the body makes an abnormal form of haemoglobin.

Approximately one per cent of the Thai population is affected by thalassaemia, and more than 30 per cent are carriers of the abnormal genes. Thalassaemia carriers are generally healthy but can pass the abnormal genes to their children, which is why it is important that any woman wanting to become pregnant undergoes screening. If you become pregnant and find out from a blood test that you have thalassaemia genes, you should seek medical advice.

Symptoms of thalassaemia include:

  • Pale appearance
  • Fatigue
  • Abdominal swelling
  • Enlarged spleen (marked splenomegaly)
  • Yellow discoloration of skin (jaundice)
  • Bone deformities in the face
  • Slow growth

The signs and symptoms the patient experience may differ depending on the type and severity of thalassaemia they have. Some show signs and symptoms of thalassaemia at birth, while others may develop signs or symptoms during the first two years of life. People with only one affected haemoglobin gene don’t experience any thalassaemia symptoms.

Thalassaemia is diagnosed through a genetic blood test and haemoglobin test. Although thalassaemia treatment is difficult and time consuming, it can be cured with a bone marrow transplant by using stem cells from the donor that match both the DNA and Human Leukocyte Antigens (HLA) of the affected individual. The most preferable donor is the patent’s sibling who has HLA matched. If there is no HLA matched sibling available, a matching unrelated donor is a viable alternative.

Without a bone marrow transplant, a child born with severe thalassaemia will face a lifetime of monthly blood transfusions. This is not without its risks, as the patient could well receive extra iron from the transfusions, which can lead to iron deposits in the liver, heart and pancreas.

The bone marrow is a blood-like tissue inside the bones. It produces new blood cells. These include red blood cells, which carry oxygen to the organs in the body; white blood cells, which help defend the body against infectious disease as part of the immune system; and platelets, which help the blood to clot. A bone marrow transplant, – today more commonly called a stem cell transplant – is a standard procedure used to treat a variety of both genetic and non-genetic blood diseases. This treatment has been used in Thailand for more than 20 years and the outcome is every bit as effective as similar treatments in Europe and America.

Advice for patients with thalassaemia:

l Eat a balanced and healthy diet with food from all five food groups

l Have a regular dental check-up every 6 months

l Avoid working too hard and playing too rough

l Do not take vitamins without medical advice

l Stay in areas that are well-ventilated so as to avoid infections

l See a doctor for treatment if you have a severe pain in your upper right abdomen, fever or jaundice

In order to avoid thalassaemia, it is important for you and your partner to have a blood test for this serious disorder. People who are carriers of a thalassaemia gene usually show no thalassaemia symptoms and we cannot know if they are carriers without a blood test. So do take time to have a screening test before having a child to avoid passing the thalassaemic gene to your offspring.

With the progress in advanced medical technology, diagnosis, effective treatment and prevention, patients can be cared for from infancy through childhood to adulthood. This progress will help thalassaemic patients to enjoy a better quality of life.

PROFESSOR EMERITUS THIP SRIPHAISAL is a Paediatric Haematologist and Oncologist at Samitivej International Children’s Hospital, |Sukhumvit Campus. Call (02) 711 8236-7.