Depression is a common mental disorder affecting more than 264 million people worldwide. It is characterized by persistent sadness and a lack of interest or pleasure in previously rewarding or enjoyable activities.  It can also disturb sleep and appetite; tiredness and poor concentration are common. Depression is a leading cause of disability around the world and contributes greatly to the global burden of disease. The effects of depression can be long-lasting or recurrent and can dramatically affect a person’s ability to function and live a rewarding life.

A person is said to have hearing loss if they are not able to hear as well as someone with normal hearing, meaning hearing thresholds of 20 dB or better in both ears. It can be mild, moderate, moderately severe, severe or profound, and can affect one or both ears. Major causes of hearing loss include congenital or early onset childhood hearing loss, chronic middle ear infections, noise-induced hearing loss, age-related hearing loss, and ototoxic drugs that damage the inner ear.

Animal influenza viruses are distinct from human seasonal influenza viruses and do not easily transmit between humans. However, zoonotic influenza viruses - animal influenza viruses that may occasionally infect humans through direct or indirect contact - can cause disease in humans ranging from a mild illness to death.

Access to good quality, affordable, and appropriate health products is indispensable to advance universal health coverage, address health emergencies, and promote healthier populations – the three strategic priorities of the World Health Organization (WHO) Thirteenth General Programme of Work 2019–2023.

Lassa fever is an acute viral haemorrhagic illness caused by Lassa virus, a member of the arenavirus family of viruses.  

Humans usually become infected with Lassa virus through exposure to food or household items contaminated with urine or faeces of infected Mastomys rats. The disease is endemic in the rodent population in parts of West Africa.  

Lassa fever is known to be endemic in Benin, Ghana, Guinea, Liberia, Mali, Sierra Leone, Togo and Nigeria, but probably exists in other West African countries as well.  

The leishmaniases are a group of diseases caused by protozoan parasites from more than 20 Leishmania species. These parasites are transmitted to humans by the bite of an infected female phlebotomine sandfly, a tiny – 2–3 mm long – insect vector.

There are three main forms of the disease: cutaneous leishmaniasis (CL), visceral leishmaniasis (VL), also known as kala-azar, and mucocutaneous leishmaniasis (MCL). CL is the most common form, VL is the most severe form and MCL is the most disabling form of the disease.

Symptoms may occur within 1 year but can also take as long as 20 years or even more to occur.

Clinical signs are easy to observe. Skin lesion has usually a different pigmentation than the surrounding normal skin (less pigmented, reddish or copper-coloured) and may have various aspects (flat, raised or nodules). Skin lesion can be single or multiple and may show a loss of sensation in the skin.

Skin smears are also used to diagnose leprosy.

People infected with filariasis who have microfilaraemia or a positive antigen test should receive antifilarial drug treatment to eliminate microfilariae. Unfortunately, the medicines available have limited effect on adult worms. Treatment also involves the management of morbidity and disability prevention (MMDP) that includes simple hygiene measures, such as basic skin care and exercise, to prevent acute attacks and progression of lymphoedema to elephantiasis. For management of hydrocoele, surgery may be appropriate.

There is as yet no proven treatment available for Marburg virus disease. However, a range of potential treatments including blood products, immune therapies and drug therapies are currently being evaluated. Supportive care – rehydration with oral or intravenous fluids – and treatment of specific symptoms improves survival. 

Illness caused by Marburg virus begins abruptly, with high fever, severe headache and severe malaise. Muscle aches and pains are a common feature. Severe watery diarrhoea, abdominal pain and cramping, nausea and vomiting can begin on the third day. Diarrhoea can persist for a week. The appearance of patients at this phase has been described as showing “ghost-like” drawn features, deep-set eyes, expressionless faces and extreme lethargy. A non-itchy rash has been noted between 2 and 7 days after the onset of symptoms. 
 

Universal health coverage can only be achieved when there is affordable access to safe, effective and quality medicines and health products. WHO works with partners and Member States to strengthen regulation, including post-marketing surveillance, and to eliminate substandard and falsified medicines. It also develops international norms and standards so that countries worldwide can regulate health products and technologies consistently.

Mental health conditions are increasing worldwide. Mainly because of demographic changes, there has been a 13% rise in mental health conditions and substance use disorders in the last decade (to 2017). Mental health conditions now cause 1 in 5 years lived with disability. Around 20% of the world’s children and adolescents have a mental health condition, with suicide the second leading cause of death among 15-29-year-olds. Approximately one in five people in post-conflict settings have a mental health condition.

WHO works with Member States and partners to prevent micronutrient deficiencies though a number of programmes and following the WHO 2016–2025 nutrition strategy. These programmes include iron and folic acid supplementation, high dose vitamin A supplementation, the promotion of breastfeeding, fortification of foods with micronutrients, and healthy, diverse diets containing foods naturally rich in vitamin and minerals.

Monkeypox virus is an orthopoxvirus that causes a disease with symptoms similar, but less severe, to smallpox. While smallpox was eradicated in 1980, monkeypox continues to occur in countries of Central and West Africa. 

Monkeypox is a zoonosis: a disease that is transmitted from animals to humans. Cases are often found close to tropical rainforests where there are animals that carry the virus. Evidence of monkeypox virus infection has been found in animals including squirrels, Gambian poached rats, dormice, different species of monkeys and others. 

Monkeypox presents with fever, an extensive characteristic rash and usually swollen lymph nodes. It is important to distinguish monkeypox from other illnesses such as chickenpox, measles, bacterial skin infections, scabies, syphilis and medication-associated allergies.