Viral hepatitis may present in acute or chronic forms and are caused by the five unrelated hepatotropic viruses Hepatitis A, Hepatitis B, Hepatitis C, Hepatitis D, and Hepatitis E as well as by other viruses (Herpes simplex, cytomegalovirus, Epstein-Barr virus, and Yellow fever virus). Only hepatitis B and C are typically sexually transmitted. Although hepatitis A can be spread through personal – including sexual – contact, it is not recognized as a venereal disease.


Hepatitis B

Hepatitis B may be acute and chronic. The incubation period is 45-160 days. Chronic hepatitis is more frequent among subjects with a subclinical course of the primary infection who are unable to eliminate the virus after the initial infection. This is typical for perinatally infected children, out of which 90% will get a chronic infection. In younger adults, the risk is 5 to 10%.

Transmission may occur through blood (now rare), tattoos, by sexual intercourse or contact with blood or bodily fluids, or by breastfeeding. There is little evidence of trans-placental crossing. However, the source of infection cannot be determined in about half of cases. Blood contact can occur by sharing syringes, shaving accessories such as razor blades, or contact with the wound of an infected person. Hepatitis B may therefore constitute a particular risk for the officer in charge of medical treatment on board, who should therefore be vaccinated.

Antibodies are present in patients with chronic hepatitis B, but these are insufficient to clear the virus, thus only serving as markers of infection. The continued production of virus combined with antibodies causes the immune complex disease seen in these patients.

Hepatitis B is endemic in many parts of the world – especially developing countries – and the resulting cirrhosis and hepatocellular carcinoma cause between 500,000 and 1,200,000 annual deaths per year. Antiviral treatment is effective only in about 65% of patients.

A Danish study from 1996 demonstrated a tripled rate of hepatitis B in merchant seamen mainly following intravenous drug use and casual sex abroad.70 A Norwegian study has demonstrated that the duration of employment in seafaring and the participation in casual sex abroad were independently associated with the presence of serological markers of hepatitis B.71 As would be expected, Asian seafarers have a higher prevalence than their colleagues from Western Europe and North America due to the high prevalence in their countries of origin.72

A course of three vaccines will normally provide lifelong protection, although boosters may occasionally be required.


Hepatitis C

Hepatitis C can be transmitted through contact with blood (including through sexual contact) and can cross the placenta. The incubation period is 15-150 days.

Hepatitis C remains asymptomatic for decades after which chronic hepatitis usually causes cirrhosis. A severe course of hepatitis C is likely with co-infection with hepatitis A or B. Therefore, persons with hepatitis C should be immunised against these two forms of hepatitis and should avoid alcohol consumption.

Viral levels can be reduced to undetectable levels by a combination of antiviral medications. There is no vaccine.



Infection with Herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) is categorized into one of several distinct disorders based on the site of infection. Worldwide rates of infection are between 65% and 90%. HSV-1 is more common than HSV-2, with rates of both increasing with age.

Oral herpes (cold sores) infecting the face and mouth is the most common and genital herpes the second most common form of herpes. Other outcomes include herpetic whitlow on the hands, ocular herpetic keratitis, herpes encephalitis and meningitis, and neonatal herpes. HSV-1 primarily causes mouth, throat, face, eye, and central nervous system infections while HSV-2 causes mainly anogenital infections. However, each may infect all areas.

Genital herpes is characterized by blisters and eventually wounds on the external genitals. In women, these may also appear on the cervix. It can be asymptomatic, though viral shedding may still occur. The incubation time is unknown.

The symptoms start with small blisters on red spots that break and leave an irregular, superficial and tender wound resembling a common cold sore (Figure 4). Genital herpes can be more difficult to diagnose than oral herpes since most HSV-2-infected persons have no classical symptoms. The diagnosis may also be confused with other conditions that may resemble genital herpes (fungal infection, lichen planus, atopic dermatitis, and urethritis).


Figure 4. Herpetic genital manifestations

Courtesy of Department of Dermato-venerology, Odense University Hospital


HSV infection cycles between periods of active disease presenting as infectious blisters lasting 2–21 days and remission periods, during which they disappear. The interval between the active phases, in which the disease is very contagious, can be highly variable. Triggers include changes in the immune system, such as concurrent infections, local injury and exposure to wind or ultraviolet light such as sunlight.

The virus remains life-long in the sensory ganglia. However, relapses tend to decline in frequency and severity, and after several years some people will become asymptomatic and will no longer experience outbreaks, though they may still be contagious. The frequency and severity of recurrent outbreaks vary greatly between patients. In some individuals, outbreaks can be quite debilitating with large, painful lesions persisting for several weeks, while others will experience only minor itching or burning for a few days. As with almost all STD’s, women are more susceptible to acquiring genital HSV-2 infection than men.

Herpes simplex is most easily transmitted by direct contact with a lesion or the body fluid of an infected individual. Transmission may occur through tiny breaks in the skin or mucous membranes in the mouth or genital areas. Skin-to-skin contact during periods of asymptomatic shedding through the skin occurs in most individuals infected with herpes and may represent the most common form of transmission.

Laboratory testing for presence of viral DNA is highly sensitive and specific but discouraged by high costs.

Antiviral medications cannot eradicate the virus, but may reduce the frequency, duration, and severity of outbreaks, and reduce asymptomatic shedding by 50%. Condoms protect moderately against HSV-2. The virus cannot pass through a latex condom, but it does not prevent contact with other skin areas or bodily fluids. There is an additive effect of combining antivirals with condoms. Analgesics and topical anaesthetics can relieve itching and pain.


Human immunodeficiency virus 1 and 2 (HIV 1/2) are lentiviruses (members of the retrovirus family) that cause acquired immunodeficiency syndrome (AIDS), a condition in humans in which the immune system fails, leading to life-threatening opportunistic infections. Certain malignancies are other serious consequences of infection.

Patterns of the epidemic differ between regions73. In some parts of the world, such as North America, Europe or the Philippines, HIV/AIDS mainly affects certain risk groups such as intravenous drug users, immigrants or homosexuals, but is also a threat to the general population. In other parts of the world, such as Central, Eastern and Southern Africa and some countries of the Caribbean, it is primarily seen in heterosexuals. Countries and regions such as Eastern Europe, China or India are facing new and major public health challenges due to HIV.



As a response to the increasing problem of HIV/AIDS among seafarers and in ports, many interventions have already been proposed and implemented. As early as 1989, the World Health Organization convened a consultation on AIDS and seafarers in Geneva. An Inter-Agency consultation on “HIV/AIDS Prevention in the Maritime Sector” has been convened in 1997 by the Civil-Military Alliance to Combat HIV and AIDS and the UNAIDS and hosted by the International Transport Workers Federation. The Indian Ocean Commission has conducted training of peer educators for seafarers among their member countries.50

In 2009, The International Organization of Migration conducted the very first regional workshop on HIV responses among seafarers and Southern African port-based communities such as the ports of Durban (South Africa), Dar Es Salaam (Tanzania), Maputo and Beira (Mozambique), and Walvis Bay (Namibia). With ports recognized as ‘entry points’ for diseases to enter and spread, the US government through its partner agencies implemented the Project Lighthouse in 12 of India’s port cities to build awareness on HIV/AIDS, to promote safe sexual practices, and to mobilize behaviour change among individuals who are connected to the port including seafarers, truckers, CSW’s, fishermen, etc. AIDS interventions in ports remain a major challenge.

There are recent developments in global programmes on HIV/AIDS for seafarers. One example is the “The Global Partnership on HIV and Mobile Workers in the Maritime Sector”16, 74 which aims at reducing vulnerability and HIV risk behaviour among seafarers by improved access to HIV-related services increasing the ownership of strategies to reduce HIV infection by key stakeholders, and to promote best practice in HIV voluntary counselling and testing in the context of seafarer recruitment/medical screening.

Condom use and standard precautions to minimize the risk of infections by contact to blood or body fluids, e.g. during first-aid procedures on board ships are equally effective against HIV infection.

Due to the global and mobile nature of shipping, intervention programs are hinged on the work cycle of seafaring.36 Health promotion and other interventions start from their origin countries, on board and in destination ports. Employers and port health authorities are well-positioned to tailor HIV/AIDS prevention programmes to seafarers. These need to include information on unsafe practices and precautionary measures, availability of safe medical care in ports, the offer of confidential and – if possible anonymous – HIV testing and information on treatment access in a seafarer’s home country.

Some countries provide a pre-embarkment orientation seminar on HIV/AIDS. While on board, condoms are being distributed, and peer education by use of AIDS videos and other learning materials are made available by shipping companies. In ports, seamen’s welfare centres and labour unions provide continuous support by educating seafarers of the local risks in the port’s red light districts and through distributing posters and reading materials. They advise the seafarers to stick to precautionary measures concerning medical care, sexual intercourse and activities such as tattooing in port.


Modes of transmission

HIV is transferred by blood, semen, vaginal fluid, pre-ejaculate, and breast milk. In these body fluids, HIV is present both as free particles and as virus within infected immune cells. The major routes of transmission are unsafe sex, contaminated needles and syringes, poorly controlled blood transfusions, breast milk, and perinatal transmission. Screening of blood products for HIV has largely eliminated transmission through blood transfusions or blood products in the developed world. Risk situations for seafarers include accidents and injuries, unsafe medical care provided in ports of high endemic areas, performance of medical procedures on board, unsafe blood transfusions, tattooing, piercing and unprotected sex. HIV cannot be transmitted through social or workplace contact with an infected person, and there are no documented cases of transmission through kissing.

In the last decade, the risk of infections according to different sexual practices has been studied in detail, showing that the often-cited value of 0.001 transmissions per 1000 contacts represents a lower boundary, with high variability due to transmission cofactors such as circumcision or genital ulcer disease.75 The contagiousness during sexual activity increases dramatically if one or both partners have other STD’s.

The proportion of infected prostitutes in ports is high in many parts of the world, in particular sub-Saharan Africa, Latin America, Asia and eastern Europe59, and the simultaneous presence of several STD’s may also be widespread.

Some infected individuals will, after 2-3 weeks, experience a period of sore throat, rash, swollen lymph nodes, or symptoms resembling the common cold, but many acute HIV infections pass without symptoms. After the acute infection, a patient may remain asymptomatic for many years.

HIV primarily infects cells in the immune system such as helper T cells (CD4+ T cells), macrophages, and dendritic cells. HIV infection leads to slowly declining levels of CD4+ T cells due to the CD8 cytotoxic lymphocytes that recognize and kill infected cells. Decline of the number of CD4+ T cells below a critical level, impairment of the immune system leads to progressive susceptibility to opportunistic infections. Consequently, the HIV infection in most untreated people progresses to AIDS with a variable rate of progression that is influenced by viral, host, and environmental factors. At 10 years most will have developed AIDS and symptoms such as adenopathy, anorexia, long lasting diarrhoea, weight loss, fever, malaise, and a multitude of opportunistic and potentially fatal infections of the skin, lungs (e.g. tuberculosis), and brain (e.g. toxoplasmosis).


Cure of HIV infection is not possible, but effective treatment options have existed for more than a decade with new drugs developed. For most of those treated, HIV has transformed from a lethal disease into a chronic condition that requires life-long antiviral medications.

 The initiation of treatment depends of the CD4 level in connection with the viral load and the presence of opportunistic infections. Treatment guidelines vary between countries and are constantly debated. WHO has issued guidelines for treatment based on stages of HIV disease and the availability of CD4 testing.76

 Strict adherence to therapy and close monitoring of side effects and immune status by a HIV specialist are essential for a successful outcome. Of concern is resistance of the virus to the antiviral therapy, which may require a change of the drug combination used. Nowadays a wide choice of treatment options is available. However, advanced laboratory tests, availability of antiviral drug options and access to specialist care are necessary to take full advantage of this development.

 Antiretroviral treatment reduces morbidity and normalizes the life expectancy of people infected with HIV, but antiretroviral medications still only reach about half of those in need worldwide. Treatment of the disease with successful lowering of viral load is now recognized as a powerful public health tool to reduce the risk of transmission.


Employment and HIV/AIDS

The International Labour Organisation recommendation concerning HIV and AIDS with regard to work outlines a code of practice,77 which advocates for the continuation of employment regardless of HIV status. However, the ship as a work place has always been seen as a special entity due to the limited access to medical care while on board. Even though the WHO advocates against immigration restrictions on the grounds of HIV infection, some countries have legal entry restrictions. Such restrictions may hamper seafarers’ travels although, however, they are rarely enforced. More importantly, the often-skewed perceptions on HIV and the risk of transmission on board, and concerns over liability have created a restrictive atmosphere, which tends to exclude HIV positive seafarers from work on board a ship.

 The decision on the fitness of a HIV positive person for duty on board involves in-depth knowledge of the natural course of disease, treatment options and living conditions at sea. Seafarers who contract HIV are perfectly capable of working normally. There would be no medical reasons for declaring an asymptomatic HIV positive seafarer that does not require medication as unfit. A HIV infection will only progress slowly to immunodeficiency if treatment is not available or not applied, which nowadays should not be the case in global seafaring. With a timely commence of antiretroviral therapy and subsequent regular medical control of the condition and adherence to the treatment, the seafarer may continue his work at sea. The HIV specialist will monitor drug resistance and adherence to the treatment and consider its side effects and potential interactions. The duration of the voyage, the access to medical care, the type of work on board, food restrictions, and the wishes of the seafarer are other factors to take into account by the medical examiner.

 However, the seafarer with advanced HIV infection or with presence of AIDS that requires constant therapy and access to regular medical care, which would not be available on board a ship, will be unfit for work.


Post-exposure prophylaxis with accidental exposure to blood and other fluids

In order to lower the risk of HIV infection, antiretroviral medication administered as fast as possible after exposure is now recommended by the WHO to be carried as part of the ship’s medical chest.69 However, a risk-benefit analysis by a specialized doctor in a port or through radio-medical advice is necessary before treatment is started. The decision to provide post-exposure antiviral treatment depends on a number of factors, such as the HIV status of the source individual, the nature of the body fluid involved, the severity of exposure and the period between the exposure and the beginning of treatment. In any case, a wound should be disinfected immediately. Overall, it can be assumed that the risk of occupational exposure at sea to HIV with subsequent infection is minor and limited to the treatment of injuries and procedures undertaken by health care staff in particular on passenger vessels.


Pre-employment testing for infection with HIV

In spite of the fact that selection based on HIV status for seafarers seeking employment at sea is unacceptable or illegal in many countries, HIV testing is frequently included in many schemes for pre-employment assessment of seafarers. Often, seafarers are tested for HIV as part of a panel of tests without being aware of the test being performed. This practice is linked to many practical and legal problems. In the absence of pre-test counselling the seafarers are not informed on the potential risks and benefits of being tested. Positive test are likely to cause mental stress and labelling as unfit for work at sea. Seafarers cannot be expected to be aware about treatment options in their countries and regions.

 International guidance prohibits an employer from requiring notification of the HIV-status of a worker77 but uncertainty exists if non-disclosure to the employer results in non-coverage by insurance schemes in case of acute illness caused by the HIV infection. Such issues should ideally be solved by the implementation by the company of an HIV/AIDS policy. Currently, the International Transport Workers Federation (ITF) and the IMHA in cooperation with the ILO are reshaping the workplace policy for seafarers in the light of new scientific evidence. In a statement in 2008 these organizations advocate against selection for employment based on HIV status because positivity does not pose a threat to public heath in the maritime context.78

 In summary, the main concern of the fitness decision in relation to HIV infection is in fact the vulnerability of the seafarer with regards to insufficient access to medical diagnosis and care. The risk to other crews is negligible if standard precautionary measures are observed. Cases of advanced disease should be assessed individually, but latent HIV infection is certainly not a reason to declare a person unfit for duty.



Human papillomavirus

Human papillomavirus (HPV) establishes infections in the skin and mucous membranes, many of them without long-term significance. More than 30 subtypes of HPV can be transmitted through sexual contact and infect the anogenital region. Some subtypes such as 6 and 11 cause skin warts (verrucae), but persistent infection with subtypes such as 16 and 18 may progress to carcinoma-in-situ and invasive cancer. HPV infection is the cause of almost all cervical neoplasias, but can also cause cancers of the vulva, vagina, penis, and anus.

Detection of pre-cancerous lesions with a cervical Papanicolaou (Pap) smear and subsequent management has reduced the incidence and fatalities of cervical cancer in the developed world. However, the vast majority of deaths from cervical cancer occur in developing countries. A cervical examination also detects warts and other abnormal growths, which become visible as white patches of skin after they are washed with acetic acid. New HPV DNA tests are more sensitive than smear or visual inspection, and a test developed for low-resource settings can potentially make screening feasible worldwide. HPV vaccines (Cervarix and Gardasil) prevent infection with the HPV types16 and 18 that cause 70% of cervical cancer.


Molluscum contagiosum

Molluscum contagiosum is a common infection of the skin (mainly trunk and extremities) or mucous membranes caused by a DNA poxvirus. It has a higher incidence in children, sexually active adults, and immunodeficient individuals. It is spread through direct skin-to-skin contact, including sexual contact and sharing items such as clothing or towels. The incubation period can range up to 6 months, with an average between 2 and 7 weeks.

Molluscum contagiosa is contagious until the bumps are gone. Individual lesions may go away on their own and are reported as lasting generally from 6 to 8 weeks, to 2 or 3 months. However via autoinoculation, the disease may propagate and so an outbreak generally lasts longer with mean durations variously reported as 8 months, and with a range of duration up to 5 years.

Treatment is often unnecessary depending on the location and number of lesions, and no single approach has been convincingly shown to be effective. Treatments include cryotherapy, astringents, essential oils, benzoyl peroxide, and cantharadin.