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HIV/AIDS
The human immunodeficiency virus
(HIV) is a retrovirus that infects many cells, including cells of the immune
system, destroying or impairing their functions. In the early stages of
infection, the person has no symptoms. However, as the infection progresses,
the immune system becomes weakened, and the person becomes more susceptible
to opportunistic infections.
HIV is transmitted through
unprotected sexual intercourse, transfusion of contaminated blood and sharing
of contaminated needles. It can also be passed from a mother to her infant
during pregnancy, childbirth and breastfeeding. Most of the HIV infections in Thailand
(more than 80 %) occur through heterosexual sex (Bureau of Epidemiology,
Ministry of Public Health).
To properly prevent HIV
infection, it is advised that condom is used for sexual intercourse. Good
quality condom is available in convenient stores, pharmacies, supermarkets
and vending machines at shopping malls and other public places throughout the
country. A condom, used in combination with a lubricant, is also adviced in certain sexual acts. Using condoms prevent
venereal diseases as well.
For other modes of transmission,
such as transmission of HIV through contaminated injection equipments in the
medical service or via blood transfusion, Thailand’s medical service has
strict and standardised infection control
practices. In addition, all blood donations are screened, following
international guidelines, before they are used in transfusions to recipients.
Therefore, the risk of HIV transmission via these modes is as minimal as
those of developed countries.
For travelers who may have been
exposed to HIV contaminated body fluid (such as blood, semen or vaginal
fluid), post-exposure prophylaxis (PEP) therapy, and HIV testing service, is
widely available in most major hospitals, where risk-assessment can also be
requested. However, the effectiveness of such a therapy depends on the amount
of fluid exposed to, the exposure route, co-existing injury, and the time
interval until receiving PEP. Consultation with an expert in this field is
recommended to get a more thorough information regarding PEP, HIV-testing and
counseling.
Tuberculosis
Tuberculosis, or TB is an infectious bacterial
disease caused by Mycobacteriium
tuberculosis, which most commonly affects the lungs. It is transmitted
from person to person via droplets from sneeze or cough of people in whom the
respiratory disease is active.
In healthy people, infection with
this bacterium is often devoid of any symptoms, since the intact immune
system acts to “wall off” the bacteria. In HIV infected persons, because of
the weakened immune system, the bacteria can flare up easily, and make the
HIV infected person developed TB more frequently. In Thailand, the
proportion of those TB patients who also have HIV is estimated to be around
11 % (data as of 2006).
The symptoms of active TB of the
lung are coughing, sometimes with sputum or blood, chest pains, weakness,
weight loss, fever and night sweats. Tuberculosis is treatable with a
six-month course of antibiotics.
Normally, travelers are safe from
TB when they visit places with good ventilation or engage in out door
activities. It is advisable to avoid crowded and poorly ventilated places.
It should be noted that people
who may have acquired TB during their travel to endemic countries, may not show
symptoms immediately. Therefore, when suspected symptoms develop, doctors
should be informed of the travel to TB prevalent areas to make a
comprehensive clinical assessment for proper diagnosis and treatment.
Malaria
Malaria
is caused by a parasite called Plasmodium, which is transmitted via the bites
of infected mosquitoes. In the human body, the parasites multiply in the
liver, and then infect red blood cells.
Symptoms
of malaria include fever, headache, and vomiting, and usually appear between
10 and 15 days after the mosquito bite. If not treated, malaria can quickly
become life-threatening by disrupting the blood supply to vital organs. In
many parts of the world, the parasites have developed resistance to a number
of malaria medicines.
Key
interventions to control malaria include: prompt and effective treatment with
artemisinin-based combination therapies; use of
insecticidal nets by people at risk; and indoor residual spraying with
insecticide to control the vector mosquitoes.
There
were a total of 56 895 reported patients in 2007 – 33 178 were Thais and 23
717 were foreign nationals. The most affected region is the South, followed by
the North, Central and Northeast regions.
While
travelling in Thailand,
particularly in the eastern and western border areas and big islands with
forests, it is advisable that travelers avoid trekking without any protection
from mosquito bites.
Dengue/Dengue Haemorrhagic Fever
Dengue
is transmitted by the bite of an Aedes
mosquito infected with any one of the four serotypes of the dengue virus. It
occurs in tropical and sub-tropical areas of the world. Symptoms appear 3 –
14 days after the infective bite. Dengue fever is a febrile illness that
affects infants, young children and adults.
Symptoms
range from a mild fever, to incapacitating high fever, with severe headache,
pain behind the eyes, muscle and joint pain, and rash. There are no specific
antiviral medicines for dengue. It is important to maintain hydration. Use of
acetylsalicylic acid (e.g. aspirin) and non steroidal anti-inflammatory drugs
(e.g. Ibuprofen) is not recommended.
Dengue
haemorrhagic fever (fever, abdominal pain,
vomiting, bleeding) is a potentially lethal complication, affecting mainly
children. Early clinical diagnosis and careful clinical management by
experienced physicians and nurses increase survival of patients.
There
were a total of 65 581 reported cases of dengue diseases (dengue fever,
dengue haemorrhagic fever, and dengue shock
syndrome) from all over the country. Among this number, a total of 95 were
fatal cases.
Avian Influenza
Avian
influenza (“bird flu”) is an infectious disease of birds caused by type A
strains of the influenza virus. The infection can cause a wide spectrum of
symptoms in birds, ranging from mild illness, which may pass unnoticed, to a
rapidly fatal disease that can cause severe epidemics.
Avian
influenza viruses do not normally infect humans. However, there have been
instances of certain highly pathogenic strains causing severe respiratory
disease in humans. In most cases, the people infected had been in close
contact with infected poultry or with objects contaminated by their faeces. Nevertheless, there is concern that the virus
could mutate to become more easily transmissible between humans, raising the
possibility of an influenza pandemic.
In
2006 there were three confirmed human cases of avian influenza. All of them
were male and all of them died. However, in 2007 Thailand saw no infection in
humans at all.
Cholera
Cholera is an acute intestinal
infection caused by ingestion of food or water contaminated with the
bacterium Vibrio cholerae.
It has a short incubation period, from less than one day to five days, and
produces an enterotoxin that causes a copious, painless, watery diarrhoea
that can quickly lead to severe dehydration and death if treatment is not
promptly given. Vomiting also occurs in most patients.
There were a total of 986 reported
cases of cholera in Thailand
in 2007 with seven deaths. Out of the country’s 76 provinces, cases were
reported from 50 provinces. They occur most frequently during the summer and
rainy seasons between March and September. Cholera is usually associated with
consumption of food that is not well cooked, in particular seafood.
Rabies
An acute infectious disease of
the central nervous system affecting almost all mammals, including humans. It
is caused by a virus (rhabdovirus) and usually
spread by contamination with virus-laden saliva of bites inflicted by rabid
animals. Important animal vectors include dog, cat, vampire bat, mongoose,
skunk, wolf, raccoon and fox.
There were 18 reported cases of
rabies in 2007 from 13 provinces, all of them fatal. Of these 12 were male
and 6 were female. Among these cases, 14 were Thai and 4 were foreign
nationals. In 24 of the cases the disease was contracted from dogs and in two
other cases the source was uncertain.
Prevention is by keeping away
from stray dogs mostly found in the streets and in temples. Domesticated dogs may not have been immunised against rabies and precaution is also adviced when visiting houses in Thailand.
Leptospirosis
Leptospirosis is an infection in rodents and other wild and domesticated species.
Rodents are implicated most often in human cases. The infection in man is
contracted through skin abrasions and the mucosa of the nose, mouth and eyes.
Exposure through water contaminated by urine from infected animals is the
most common route of infection. Human-to-human transmission is rare.
Outdoor
and agricultural workers (rice-paddy and sugarcane workers for example) are
particularly at risk but it is also a recreational hazard to those who swim
or wade in contaminated waters. In endemic areas the number of leptospirosis cases may peak during the rainy season and
even may reach epidemic proportions in case of flooding because the floods
cause rodents to move into the city.
Prevention
strategies of human leptospirosis include wearing
protective clothing for people at occupational risk and avoidance of swimming
in water that may be contaminated. Leptospirosis
control in animals is dependent on the serovar and
animal species but may be either vaccination, a testing or culling programme, rodent control or a combination of these
strategies.
In
2007 there were 3 279 reported cases of leptospirosis
in 73 provinces with 54 deaths. Of the total, 2 562 were male and 717 were
female. Northeastern Thailand saw the
highest number of cases followed by the North. .
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