Hong Kong (China)

• Hepatitis A is a liver infection caused by a virus.
• The virus is easily transmitted by contaminated food or water but can also be transmitted through sexual contact.
• A safe and very effective vaccine is available that affords long-lasting protection.
• Hepatitis A vaccination is recommended for all travelers going to tropical or subtropical countries, and for risk groups.

Hepatitis A occurs worldwide, but the risk of infection is higher in countries with poor hygiene conditions. There is an increased risk in most tropical and subtropical countries as well as in some countries in Eastern Europe and around the Mediterranean. Outbreaks in northern European countries can also occur when unvaccinated children become infected during family visits to tropical and subtropical countries and transmit the virus in their care facilities on their return.

In recent years, there has also been an increase in cases in North America and Europe, including Switzerland, particularly among men who have sex with men (MSM).

There is a safe and very effective vaccine that consists of two injections at least 6 months apart. It offers lifelong protection after the second dose. The hepatitis A vaccination can also be administered in combination with the hepatitis B vaccination (3 doses required if given to persons 16 years and older).

Vaccination against hepatitis A is recommended for all travellers to risk areas and for people with an increased personal risk, such as people with chronic liver disease, men who have sex with men and people with an increased occupational risk, such as in the health service or in contact with waste water.

• Federal Office of Public Health (FOPH). Hepatitis A
  
• Hepatitis Switzerland
   

• Polio is a vaccine-preventable viral disease of the nervous system that is acquired mainly through the consumption of food or water contaminated by feces.
• The infection with the polio virus can affect children and adults and may lead to permanent limb or respiratory muscle paralysis and death.
• An effective, well- tolerated vaccine is available! Check if booster doses are recommended for the travel destination (on top of completed basic vaccination schedule).

Regular hand washing after using the bathroom and before eating or preparing food. Avoidance of undercooked or raw food that is potentially contaminated with fecal material.

The most important prevention is vaccination. A very effective and well-tolerated vaccine against polio is available (inactivated (killed) polio vaccine (IPV)), which is part of the basic vaccination schedule during childhood. Combination vaccines (e.g. with diphtheria and tetanus) are also available. After basic vaccination, a booster dose is recommended every 10 years for travel to certain countries (see country page recommendations). WHO recommends a yearly vaccination for residents or long-stay visitors (minimum 4 weeks) in a country with ongoing polio infections or circulating vaccine-derived polio viruses. This recommendation not only targets individual protection, but aims to prevent the international spread of the virus.

WHO: https://www.who.int/news-room/fact-sheets/detail/poliomyelitis

FOPH Switzerland: Swiss vaccination plan: https://www.bag.admin.ch/bag/de/home/gesund-leben/gesundheitsfoerderung-und-praevention/impfungen-prophylaxe/schweizerischer-impfplan.html

• Rabies is mainly transmitted by dogs (and bats), but any mammal can be infectious.
• The disease is invariably fatal at the time when symptoms occur.
• Rabies is best prevented by a pre-travel vaccination and appropriate behavior towards mammals (avoiding contacts).
• Pre-travel vaccination (see section prevention) is also recommended because vaccines and immunoglobulins are often not available in many travel countries.  
• Attention: a bite or a scratch wound as well as a contact with mammal saliva on an open wound is always an emergency! Find out about the necessary actions below!

No treatment against rabies disease exists!

Post-exposure measures: clean the wound immediately with plenty of water and soap for 10-15 minutes, then disinfect the wound (e.g. Betadine®, Merfen®), and immediately (i.e. during the trip!) get emergency post-exposure vaccination against rabies: for those having received full pre-exposure rabies vaccination before travel, two additional vaccine shots (any available brand) at an interval of 3 days suffice and should be administered as soon as possible on site (i.e. also while travelling). If full pre-exposure vaccination has not been given, in addition to vaccination, passive immunization is required with immunoglobulins within the shortest delay on site.

Of note, immunoglobins (and sometimes vaccines) are often unavailable in low-resource settings, causing stress and uncertainty. Tetanus booster vaccination may be also warranted.

Petting any mammals while travelling is not a good idea, even if they are cute! Do not feed them! Refrain from touching wild or unfamiliar or dead animals. 

Vaccination against rabies (preexposure vaccination) is highly recommended for:

• Repeated travels or long-term stay in endemic countries.
  
• Short journeys with high individual risk, especially for travellers on ‘two wheels’ or treks in remote areas, toddlers and children.
  
• Persons, working with animals, or cave explorers (bats!).
  

The shortened vaccination schedule can be proposed to most travellers: 2 doses given at least 7 days apart before departure. A single lifetime booster dose (3rd dose) is recommended after one year or later when further travelling to rabies endemic countries is undertaken. If you have an immune deficiency, please consult your doctor, as different vaccination intervals apply to you.

• In case of trips planned, schedule a visit at the travel clinic 4 weeks before departure at the latest. But if it's really urgent, an appointment 10 days before departure will suffice.
  
• After exposure (bite, scratch injury): seek medical attention immediately (meaning even during travel!) to get wound treatment and postexposure vaccinations against rabies! This is also necessary even for those with a completed series of basic vaccinations before travel!
• This information leaflet should be printed and kept handy during the trip!

• FOPH Switzerland (German): LINK

• Viral disease transmitted by night-biting mosquitoes in rural/suburban areas.
• Very rare in travelers.
• Mostly mild or without symptoms; severe illness is rare but has a high mortality.
• Vaccine available for those at increased risk, such as long-term travelers to endemic areas.

• WHO Factsheet Japanese Encephalitis: https://www.who.int/news-room/fact-sheets/detail/japanese-encephalitis
• Solomon et al., Japanese Encephalitis, BMJ 2000: https://jnnp.bmj.com/content/jnnp/68/4/405.full.pdf
• CDC Japanese Encephalitis: https://www.cdc.gov/japaneseencephalitis/index.html 

• Dengue fever is the world's most common insect-borne infectious disease.
• Great attention should be paid to mosquito protection during the day!
• The disease can cause high fever, muscle and joint pain, and skin rashes. In rare cases, bleeding may occur. There is no specific treatment. Vaccination is recommended only for people with evidence of previous dengue infection.
• For personal safety, we strongly recommend that you inform yourself in detail about dengue.

Dengue fever is the most common insect-borne infectious disease worldwide. There are 4 known serotypes of dengue virus, so it is possible to be infected with dengue more than once. Approximately 1 in 4 infected individuals develop symptoms of dengue, resulting in high fever, muscle and joint pain, and skin rash. In rare cases, most often after a second infection, life-threatening bleeding and shock (severe drop of blood pressure) may occur.

In 3 out of 4 cases, an infection with the virus remains asymptomatic. After a short incubation period (5-8 days), 1 out of 4 infected people present an abrupt onset of fever, headache, joint, limb and muscle pain, as well as nausea and vomiting. Eye movement pain is also typical. A rash usually appears on the 3rd or 4th day of illness. After 4 to 7 days, the fever finally subsides but fatigue may persist for several days or weeks.

In rare cases, severe dengue can occur. Particularly susceptible are local children and seniors as well as people who have experienced a prior dengue infection. Tourists extremely rarely present with severe dengue. In the first days, the disease resembles the course of classic dengue fever, but on the 4th/5th day, and usually after the fever has subsided, the condition worsens. Blood pressure drops, and patients complain of shortness of breath, abdominal discomfort, nosebleeds, and mild skin or mucosal hemorrhages. In the most severe cases, life-threatening shock may occur.

There is no specific treatment for dengue virus infection. Treatment is limited to mitigation and monitoring of symptoms: fever reduction, relief of eye, back, muscle and joint pain, and monitoring of blood clotting and blood volume. Patients with severe symptoms must be hospitalised.

For treatment of fever or pain, paracetamol or acetaminophen are recommended (e.g. Acetalgin® Dafalgan®). Drugs containing the active ingredient acetylsalicylic acid (e.g. Aspirin®, Alcacyl®, Aspégic®) must be avoided.

Effective mosquito protection during the day and especially during twilight hours (i.e. sunset) is the best preventive measure:

1. Clothing: Wear well-covered, long-sleeved clothing and long pants and treat clothing with insecticide beforehand (see factsheet “prevention of arthropod bites”).
2. Mosquito repellent: Apply a mosquito repellent to uncovered skin several times a day (see factsheet “prevention of arthropod bites”).
3. Environmental hygiene: Do not leave containers with standing water (coasters for flower pots, etc.) in your environment to avoid mosquito breeding sites.

For further information, please refer to the factsheet on "Mosquito and tick bite protection".

Note on the dengue vaccine Qdenga®:

• Based on the data available, many European countries, as well as the Swiss Expert Committee for Travel Medicine (ECTM), currently recommend vaccination with Qdenga® only for travelers who have evidence of a previous dengue infection and who will be exposed in a region with significant dengue transmission. This is a precautionary decision, since the current data also include the possibility that people who are vaccinated with Qdenga® before a first dengue infection may experience a more severe course of the disease. A consultation with a specialist in tropical and travel medicine is recommended.

Consistent mosquito protection during the day (see above) is still considered the most important preventive measure against dengue!

Of note

• Do not take any products containing the active ingredient acetylsalicylic acid (e.g. Aspirin®, Alcacyl®, Aspégic®) if you have symptoms, as they increase the risk of bleeding in the event of a dengue infection!
• However, do not stop taking medications containing acetylsalicylic acid if it is already part of your regular treatment for an underlying condition.

• Do not take any products containing the active ingredient acetylsalicylic acid (e.g. Aspirin®, Alcacyl®, Aspégic®) if you have symptoms, as they increase the risk of bleeding in the event of a dengue infection!
• However, do not stop taking medications containing acetylsalicylic acid if it is already part of your regular treatment for an underlying condition.

• Chikungunya fever is a viral infection that is transmitted by mosquitoes. 
• The disease typically manifests itself with fever and severe joint pain in the hands and feet, which can last for weeks to months in some patients.
• Chikungunya fever can be prevented by protecting yourself from mosquito bites.
  

The infection may cause some or all of the following symptoms: sudden onset of high fever, headache, muscle and joint pain, joint swelling, rash. The rash usually appears after the onset of the fever and usually affects the trunk and extremities. The joint pain and swelling usually occur symmetrically on both sides and mainly affect the hands and feet - but larger joints such as the knees or shoulders can also be affected. The intense joint pain can be very debilitating for those affected.

Around 5 - 10 % of those infected have persistent severe joint and limb pain even after the fever has subsided, which in some cases lasts for several months or, although rarely, even years.

Preventive measures against mosquito bites during the day: Apply mosquito repellent to uncovered skin; wear long clothing; treat clothing with insecticide. For more information, see the information sheet "Protection against insect and tick bites". Another very important protective factor is so-called 'environmental hygiene': breeding sites for mosquitoes in the immediate vicinity of human dwellings should be avoided by removing all forms of containers with water (e.g. flowerpot saucers, uncovered water containers, etc.).

Vaccination: Two Chikungunya vaccines are currently approved in the US and EU (IXCHIQ® and VIMKUNYA®), but not yet in Switzerland. The Swiss Expert Committee for Travel Medicine is currently reviewing the recommendation for travellers.

• BAG Switzerland EN
  
• WHO - Chikungunya information sheet EN
  
• Centre for Disease Control and Prevention (CDC) EN
• European Centre for Disease Prevention and Control (ECDC) EN

• Marburg virus disease is a rare but severe hemorrhagic fever.
• The disease spreads through contact with infected animals or people.
• Symptoms can be similar to other tropical diseases
• There is no licensed treatment or vaccine for Marburg disease, and
• Prevention measures are important to follow, see below.

The incubation period (time between infection and onset of symptoms) ranges from a 2 to 21 days (usually 5 to 10 days). The onset of MVD is usually abrupt, with initially non-specific, flu-like symptoms such as a high fever, severe headache, chills and malaise. Rapid worsening occurs within 2–5 days for more than half of patients, marked by gastrointestinal symptoms such as anorexia, abdominal discomfort, severe nausea, vomiting, and diarrhoea. As the disease advances, clinical manifestations can become more severe and include liver failure, delirium, shock, bleeding (hemorrhaging), multi-organ dysfunction and death.

In case of symptoms

If think that you have had an exposure at risk and develop fever with nonspecific symptoms such as chills, headache, muscle pain, malaise or abdominal pain:

• you should separate yourself from others (isolate) immediately and
• immediately seek medical advice by contacting the in-country hotline by phone or contact a tropical institute or university hospital infectious disease unit.
• alert the healthcare providers of your recent travel to an area with a Marburg outbreak.

The risk for travellers is  very low if the below precautions are followed, but it is high for family members and caregivers who have contact with sick people.

General precautions during travel to affected areas:

• Wash your hands regularly and carefully using soap and water (or alcohol gel if soap is unavailable).
  
• Avoid contact with sick people who have symptoms, such as fever, muscle pain, and rash.
  
• Avoid contact with blood and other body fluids
  
• Avoid visiting healthcare facilities in the MVD-affected areas for nonurgent medical care or non-medical reasons.
  
• Avoid contact with dead bodies or items that have been in contact with dead bodies, participating in funeral or burial rituals, or attending a funeral or burial. 
  
• Avoid handling, cooking, or eating bush/wild meat (meat of wild/feral mammals killed for food).
• Wash and peel fruit and vegetables before consumption.
  
• Avoid visiting mines or bat caves and contact with all wild animals; alive or dead, particularly bats.
  
• If you decide to visit mines or caves inhabited by fruit bat colonies, wear gloves and other appropriate protective clothing, including masks and eye protection.
  
• Practice safer sex.

• Swiss Federal Office of Public Health: LINK
  
• European Center for Disease Control and Prevention (ECDC): Marburg virus disease
  
• US Center for Disease Control and Prevention (CDC): About Marburg Disease
• World Health Organization: Marburg Virus Disease

• Zika is a viral disease transmitted by mosquitoes that bite during the day.
• Zika virus infection during pregnancy (any trimester) can cause fetal malformation.
• In areas at increased risk of transmission (epidemic), specific recommendations must be given to women who are – or wish to become – pregnant.
  

The Zika virus was identified in 1947 in monkeys from the Zika forest in Uganda. Virus circulation has long been limited (a few cases each year) in Africa and South-East Asia. In May 2015, the American continent was affected for the first time, with an epidemic in Brazil that rapidly spread to South America, Central America, and the Caribbean. Since then, the disease has been reported in most tropical and subtropical regions.

The risk of infection is currently low in most regions and does not require specific measures. However, epidemics may occasionally reappear. During epidemics, the risk of transmission is high, and specific recommendations for the traveller are necessary.

In case of fever, it is recommended to consult a doctor. The symptoms of a Zika virus infection may seem similar to those of malaria, for which urgent treatment is necessary, or dengue fever. Treatment for Zika aims for reduction of fever and joint pain (paracetamol). Avoid aspirin and anti-inflammatory drugs (e.g. ibuprofen) as long as dengue fever is not excluded. There is no vaccine available.

In case of pregnancy and fever during or upon return from a Zika virus transmission area, blood and/or urine tests are indicated. In case of confirmed infection, the medical management should be discussed with the gynecologist and infectious/travel medicine specialists.

The risk of infection can be reduced by effective protection from mosquito bites during the day and in the early evening (long clothing, mosquito repellents, mosquito net).

When travelling in an area of increased risk (= declared epidemic) and in order to prevent possible sexual transmission of the virus, it is recommended to use a condom / Femidom during the trip and at least 2 months after return.

Due to the risk of fetal malformation, pregnant women are advised against travelling to areas at increased risk (= declared as epidemic) of Zika transmission at any time during pregnancy (in case of essential travel, a consultation with a travel medicine specialist is advised before departure). Women who wish to become pregnant should wait at least 2 months after their return (or that of their partner) from an area at increased risk of Zika transmission.

• Zika virus infection during pregnancy (any trimester) can cause fetal malformation.
• For most up-to-date information on Zika distribution and / or Zika outbreaks, please consult CDC Zika Travel Information: https://wwwnc.cdc.gov/travel/page/zika-information 

• Mpox is a viral disease that typically causes a rash, swollen lymph nodes and fever.
• An emerging variant is spreading rapidly in eastern D.R. Congo and neighboring countries prompting a new WHO declaration of a public health emergency of international concern (PHEIC), as of August 14th 2024.
• Close physical contact (sexual or non-sexual) is the main mode of transmission.
• The disease generally follows a mild course. Children, pregnant women, and people with weak immune systems are the most at risk of complications.
• Vaccination against mpox is available, but limited to groups at high risk of exposure. 

Mpox has been commonly found in West and Central Africa for many years where the suspected reservoir - small mammals - is endemic. There are two types of Monkeypox virus called ‘clades’ that cause the disease mpox - clade I in Central Africa and clade II in West Africa. Since the end of smallpox vaccination campaigns in the early 1980’s, cases of mpox have increased, slowly at first and significantly in the last 5-10 years, especially in the Democratic Republic of Congo (DRC).

In 2022, a new emerging subclade of clade II was responsible for a global epidemic that spread mainly through sexual contact among men who have sex with men. It resulted in the first public health emergency of international concern (PHEIC) declared by the WHO until 2023. Although the clade II epidemic is now under control, this virus variant continues to circulate worldwide.

In 2024, the continued spread of mpox clade I in endemic regions of Central Africa, particularly in the DRC, and the emergence of a new subclade Ib in Eastern DRC and neighboring countries have raised global concern and prompted the WHO to declare a PHEIC for the second time in two years. The current geographical spread of the mpox clade Ib variant occurs via commercial routes through sexual contact (e.g. sex workers), followed by local transmission in households and other settings (which is becoming increasingly important).

Animal to human transmission
Mpox can spread from animal to human when they come into direct contact with an infected animal (rodents or primates).

Human to human transmission
Mpox can be spread from person to person through close physical contact (sexual and non-sexual contact) with someone who has symptoms of mpox. Skin and mucous membrane lesions, body fluids, and scabs are particularly infectious. A person can also become infected by touching or handling clothing, bedding, towels, or objects such as eating utensils/dishes that have been contaminated by contact with a person with symptoms. Household members, family caretakers, and sexual partners of a confirmed case of mpox are at higher risk for infection as are health care workers who treat a case without adequate personal protection.

The incubation period (time between infection and onset of symptoms) ranges from a few days up to 3 weeks. Mpox causes a rash / skin eruption that can be painful associated with swollen lymph nodes and fever. Fever may start already before the rash phase. Other symptoms include muscle aches, back pain, and fatigue. The rash may be localized or generalized, with few or hundreds of skin lesions. It mainly affects the face, the trunk and the palms of hand and soles of the feet. It can also be present in genital areas and on mucous membranes such as in the mouth and throat. Symptoms usually last 2 to 4 weeks and the person remains contagious until all lesions have healed (once the cabs have fallen off).

Complications include secondary bacterial infections, infections of the lung and brain and involvement of other organs, still birth and others. Children, pregnant women, and people with weak immune systems are at higher risk to develop a severe form of mpox.

The majority of person with mpox recovers spontaneously and do not need specific antiviral treatment. Care management consists of relieving pain and other symptoms and preventing complications (e.g., superinfection). Several antiviral treatments are studied in various countries and may be used in trials or in clinical situations according to the recommendations of national medical societies.

In case of symptoms: 

• Seek medical attention immediately
• If you are diagnosed with mpox
  • Please stay at home (isolate yourself) until your mpox rash has healed and a new layer of skin has formed. Staying away from other people and not sharing things you have touched with others will help prevent the spread of mpox. People with mpox should regularly clean and disinfect the spaces they use to limit household contamination.
  • Wash your hands often with soap and water or an alcohol-based hand sanitiser containing at least 60% alcohol.
  • You should not have sex while symptomatic and while you have lesions or symptoms. Use condoms for 12 weeks after infection. This is a precaution to reduce the risk of spreading the virus to a partner.
  • For more information on what do if you are sick, see CDC LINK.

General precautions:

• Worldwide:
  • avoid close, skin-to-skin contact with people who have or may have mpox or people who have a rash (e.g., pimples, blisters, scabs).
  • Wash your hands often with soap and water or an alcohol-based hand sanitiser containing at least 60% alcohol.
  • Avoid touching potentially contaminated personal items such as cups, bedding/clothing, towels or sharing eating utensils/cups, food or drink with a person who has, or may have mpox.
  • Avoid sex with sick persons; use of condoms for up to 12 weeks if you sexual partner have had mpox.
  • Follow advice of local authorities.

• When travelling to endemic / epidemic areas in Africa, in addition to above mentioned general precautions: 
  • Avoid contact with and animals in areas where mpox regularly occurs.
  • Avoid eating or preparing meat from wild animals (bushmeat) or using products (creams, lotions, powders) derived from wild animals.

Vaccination:

There are several vaccines against mpox (e.g. Jynneos®, manufacture Bavarian Nordic). The Bavarian Nordic vaccine was originally developed to fight against smallpox, but offers a cross-protection against mpox. In Switzerland, the Jynneos® vaccine has been licensed by Swissmedic since 2024. Groups at risk (e.g., men who have sex with men or transgender people with multiple sex partners) are eligible for vaccination since 2022 and this recommendation remains unchanged (see FOPH recommendations). In light of the epidemiological situation in Africa in 2024, the Swiss Expert Committee for Travel Medicine recommends vaccination against mpox for professionals who are / will be in contact with suspect mpox patients or animals in endemic/epidemic regions or who work in a laboratory with the virus (for updates, see news).

The risk to the general population and travelers (tourists) is considered extremely low if the above-mentioned general precautions are followed and vaccination is not recommended.

• Seek medical attention immediately.
• Mpox is not a sexual transmitted disease in the strict sense, physical contact with a person with symptoms of mpox (rash at any stage) is sufficient to transmit the disease. Condoms do not protect you from getting mpox!

• Swiss Federal Office of Public Health (FOPH)                                                            
• World Health Organisation: WHO FAQ
• European Center of Disease Control and Prevention (ECDC)
• US Center of Disease Control and Prevention (CDC)

• Geschlechtskrankheiten sind ein weltweit verbreitetes Gesundheitsproblem und können durch Prävention, regelmässiges Testen und Behandlung in den Griff bekommen werden.
• Das Wissen um Risiken sowie Safer-Sex-Praktiken inklusive Kondomgebrauch sind wichtig. Falls Sie mehr dazu erfahren wollen, wie Sie sich während der Reise optimal schützen können, besprechen Sie dies mit einer Fachperson.
• Hatten Sie eine Risikosituation, ist es wichtig mit einer Fachperson so rasch wie möglich Rücksprache zu halten, um zu erörtern, ob eine HIV-Post-Expositions-Prophylaxe (PEP) durchgeführt werden soll, um eine Ansteckung mit HIV zu verhindern.
• Im Nachgang einer Risikosituation ist es wichtig sich auf Geschlechtskrankheiten testen zu lassen. Auch dann, wenn Sie keine Symptome haben.

• Brennen oder Juckreiz im Genitalbereich
  
• Schmerzhaftes oder häufiges Wasserlösen oder auch Schmerzen im Unterleib
  
• Ungewöhnlicher Ausfluss aus dem Penis oder der Vagina
  
• Wunden, Rötungen, Bläschen im Mund/Lippen oder Genitalbereich sowie Warzen im Intimbereich
  
• Manchmal auch Fieber (eher selten)
  

Wichtig: Eine STI kann auch ohne oder mit nur leichten Symptomen auftreten. Auch wenn Sie sich dessen nicht bewusst sind, können Sie andere anstecken. Deshalb ist es wichtig sich testen zu lassen.

• Beachten Sie die Safer Sex Regeln von Love Live. Dazu gehört auch bei jedem Anal- oder Vaginalverkehr Kondome zu verwenden.
  
• Denken Sie daran, dass es bei Oralverkehr auch zu Übertragungen von STIs kommen kann.  
  
• Lassen Sie sich impfen! Es gibt Impfstoffe zum Schutz vor HPV, Hepatitis A und Hepatitis B.
  
• Hatten Sie eine Risikosituation, ist es wichtig mit einer Fachperson so rasch wie möglich Rücksprache zu halten, um zu erörtern, ob eine HIV-Post-Expositions-Prophylaxe (PEP) durchgeführt werden soll, um eine HIV-Infektion zu verhindern. Am wirksamsten ist eine HIV-PEP innerhalb weniger Stunden danach.
  
• Es gibt auch weitere Präventionsmassnahmen für spezielle Situationen (Präexpositionsprophylaxe HIV-PrEP). Sprechen Sie mit einer damit erfahrenen Fachperson vor Abreise darüber.
  
• Denken Sie daran, dass Alkohol oder Drogen zu erhöhtem Risikoverhalten führen.
  
• Denken Sie daran, dass Sie eine weitere Person/bekannter Partner*in bei ungeschütztem Sex anstecken können, sofern bei Ihnen eine unbehandelte STI vorliegt.
  
• Menschen mit einer neu diagnostizierten STI sind angehalten ihre früheren Sexualpartner*innen zu informieren, damit auch sie behandelt werden können.

Durch Bakterien oder Parasiten hervorgerufen
Alle diese Krankheiten können geheilt werden. Wichtig ist dabei, frühzeitig zu testen und umgehend zu therapieren, um Komplikationen und v.a. weitere Übertragungen zu vermeiden.

• Syphilis
  Auch bekannt als Lues. Sie wird durch das Bakterium Treponema pallidum verursacht. Das erste Anzeichen ist eine schmerzlose Wunde an den Genitalien, im Mund, auf der Haut oder im Rektum, die hochgradig ansteckend ist und nach 3 bis 6 Wochen spontan abklingt. Da diese schmerzlos ist, nehmen nicht alle Patienten*innen diese Läsion wahr. Oft heilt diese Infektion jedoch nicht von selbst aus. In der zweiten Phase können Hautausschlag, Halsschmerzen und Muskelschmerzen auftreten. Unbehandelt kann die Krankheit im Verborgenen (latent) bleiben, ohne dass Symptome auftreten. Etwa ein Drittel der Infizierten mit unbehandelter Syphilis entwickelt im Verlauf Komplikationen. Diese Spätform wird als  sogenannt tertiäre Syphilis bezeichnet . In diesem Stadium kann die Krankheit alle Organe befallen: am häufigsten das Gehirn, die Nerven und die Augen. Die Infektion kann während der Schwangerschaft auf den Fötus und bei der Geburt auf das Kind übertragen werden.
  
  
• Chlamydia trachomatis
  Chlamydien können ungewöhnlichen Ausfluss aus dem Penis oder der Vagina, Unbehagen beim Wasserlösen und Unterleibsschmerzen verursachen. Oft treten keine Symptome auf. Unbehandelt können sie zu Unfruchtbarkeit führen und die Krankheit kann auf Sexualpartner*innen übertragen werden. Die Bakterien können auch während der Schwangerschaft auf den Fötus, oder während der Geburt auf das Kind übertragen werden und Augeninfektionen oder Lungenentzündungen verursachen.
  
  
• Gonorrhoe
  Auch bekannt als Tripper. Zu den häufigsten Symptomen gehören Ausfluss aus der Vagina oder dem Penis und schmerzhaftes Wasserlassen. Symptome müssen aber nicht immer auftreten. Sowohl bei Männern als auch bei Frauen kann Gonorrhoe auch den Mund, den Rachen, die Augen und den Anus infizieren und sich auf das Blut und die Gelenke ausbreiten, wo sie in eine schwere Krankheit übergehen kann. Bleibt sie unbehandelt, kann sie eine Beckenentzündung verursachen, die zu chronischen Beckenschmerzen und Unfruchtbarkeit führen kann. Die Krankheit kann während der Schwangerschaft auf den Fötus übertragen werden.
  
  
• Weitere bakterielle STIs: Mykoplasmen und Ureaplasmen. Diese können ebenfalls behandelt werden.
  
  
• Trichomoniasis
  Sie wird durch einen Parasiten verursacht, der mit einer einzigen Dosis eines Antibiotikums behandelt werden kann. Trichomoniasis kann bei Frauen einen übel riechenden Scheidenausfluss, Juckreiz im Genitalbereich und schmerzhaftes Wasserlassen verursachen. Bei Männern treten in der Regel weniger oder keine Symptome auf. Zu den Komplikationen gehört das Risiko einer vorzeitigen Entbindung bei schwangeren Frauen. Um eine Reinfektion zu verhindern, sollten beide Sexualpartner behandelt werden.
  
  

Durch Viren hervorgerufen

• HIV/AIDS - siehe Informationsblatt HIV-AIDS
  
  
• Herpes simplex Virus
  Im Lippen-Mundbereich, auch bekannt als Fieberbläschen, ist nicht heilbar. Herpes kann aber mit Medikamenten bei akuten Beschwerden kontrolliert werden. Die Symptome sind in der Regel schmerzhafte, wässrige Hautbläschen und finden sich an oder um die Genitalien, den Anus oder den Mund. Nach der Erstinfektion ruht das Virus im Körper und die Symptome können über Jahre hinweg wieder auftreten. Schwangere Frauen können die Infektion an ihre Neugeborenen weitergeben, was zu einer bedrohlichen Infektion führen kann.
  
  
• Virale Hepatitis (siehe auch Hepatitis Schweiz)
  
  • Hepatitis A (HAV)
    Hepatitis A ist eine durch Impfung vermeidbare Leberinfektion, die durch das Hepatitis-A-Virus verursacht wird. Das Hepatitis-A-Virus findet sich im Stuhl und im Blut infizierter Personen. Hepatitis A kann durch verunreinigtes Wasser und Lebensmittel sowie bei anal-oralen sexuellen Aktivitäten übertragen werden. Die Patienten*innen leiden an einer akuten und oft schweren Erkrankung, erholen sich aber allermeist spontan.
    
  • Hepatitis B (HBV)
    Das Hepatitis-B-Virus wird durch sexuelle Kontakte sowie durch den Kontakt mit anderen Körperflüssigkeiten, wie z.B. Blut, übertragen. Zur Übertragung kann es z.B. auch bei medizinischen Eingriffen oder Brennen eines Tatoos unter nicht optimalen hygienischen Bedingungen kommen. Hepatitis B kann eine schwere Leberinfektion verursachen, die sowohl zu einer sofortigen Erkrankung, als auch zu einer lebenslang andauernden Infektion führen kann mit möglicher Folge einer dauerhaften Lebervernarbung (Zirrhose) und Krebs. Schwangere Frauen mit Hepatitis B können das Virus während der Geburt auf ihr Kind übertragen. Zu Beginn der Infektion haben Sie möglicherweise keine Symptome.  Das Virus kann auf Sexualpartner*innen übertragen werden. Hepatitis B kann mit antiviralen Medikamenten behandelt werden, ist aber nur selten heilbar. Eine Impfung kann eine Hepatitis-B-Infektion verhindern.
    
  • Hepatitis C (HCV)
    In den meisten Fällen wird Hepatitis C durch den Kontakt mit infiziertem Blut übertragen. Seltener kann es durch analen Sexualkontakt oder von der Mutter auf das Kind während der Schwangerschaft und Geburt übertragen werden. Die meisten Infizierten sind sich ihrer Infektion nicht bewusst, weil sie keine Symptome entwickeln, aber diese chronische Infektion kann zu Leberzirrhose und Krebs führen. Hepatitis C kann behandelt werden, eine Impfung gibt es nicht.
    
    
• Humanes Papillomavirus (HPV)
  HPV ist die häufigste Geschlechtskrankheit. Es gibt eine Vielzahl verschiedener HPV-Typen, und einige von ihnen können Genital-, Anal- und Mundwarzen sowie Gebärmutterhals-, Penis- oder Rachenkrebs verursachen. Die Symptome können auch noch Jahre nach dem Sex mit einer infizierten Person auftreten. Zwei verfügbare Impfstoffe schützen gegen die wichtigsten HPV-Typen, die Gebärmutterhals-, Penis- oder Analkrebs verursachen.
  
  
• Zika - siehe Informationsblatt Zika
  In den meisten Fällen wird es vor allem durch Stechmücken übertragen. Es kann aber auch sexuell übertragen werden. Eine Ansteckung mit Zika während der Schwangerschaft kann bei dem sich entwickelnden Fötus Geburtsfehler wie Mikrozephalie (kleiner Kopf mit neurologischen Ausfällen) verursachen. Die einzige Möglichkeit, eine sexuelle Übertragung des Virus während der Schwangerschaft zu verhindern, besteht darin, Vorsichtsmassnahmen (Kondome) zu treffen oder Sex (mindestens 2 Monate nach der Rückkehr) mit jemandem zu vermeiden, der kürzlich in ein Risikogebiet gereist ist, auch wenn der Reisende keine Symptome hat.

• Love Life: www.lovelife.ch 
  
• Sexuelle Gesundheit Schweiz: www.sexuelle-gesundheit.ch 
  
• Hepatitis Schweiz: https://hepatitis-schweiz.ch/formen/was-ist-hepatitis 
  
• World Health Organization (WHO). Factsheets. Sexually transmitted infections (STIs). 14 June 2019: www.who.int/news-room/fact-sheets/detail/sexually-transmitted-infections-(stis) 
  
• Centers for Disease Control and Prevention (CDC). Factsheet: Information for Teens and Young Adults: Staying Healthy and Preventing STDs (2017): www.cdc.gov/std/life-stages-populations/stdfact-teens.htm 
  
• Centers for Disease Control and Prevention (CDC). How You Can Prevent Sexually Transmitted Diseases: www.cdc.gov/std/prevention/ 
  
• Centers for Disease Control and Prevention (CDC) Sexual Transmission and Prevention. Zika Virus: www.cdc.gov/zika/prevention/protect-yourself-during-sex.html 
  
• Centers for Disease Control and Prevention (CDC) Zika and Pregnancy; Pregnant Women and Zika (March 2021): www.cdc.gov/pregnancy/zika/protect-yourself.html