Though heart disease is not exclusive to the poor, there are aspects of a life of poverty that contribute to its development. This category includes coronary heart disease, stroke and heart attack. Heart disease is the leading cause of death worldwide and there are disparities of morbidity between the rich and poor. Studies from around the world link heart disease to poverty. Low neighborhood income and education were associated with higher risk factors. Poor diet, lack of exercise and limited (or no) access to a specialist were all factors related to poverty, though to contribute to heart disease.

Both low income and low education were predictors of coronary heart disease, a subset of cardiovascular disease. Of those admitted to hospital in the United States for heart failure, women and African Americans were more likely to reside in lower income neighborhoods. In the developing world, there is a 10 fold increase in cardiac events in the black and urban populations.

More than 300 million people worldwide have asthma. The rate of asthma increases as countries become more urbanized and in many parts of the world those who develop asthma do not have access to medication and medical care. Within the United States, African Americans and Latinos are four times more likely to suffer from severe asthma than whites. The disease is closely tied to poverty and poor living conditions. Asthma is also prevalent in children in low income countries. Homes with roaches and mice, as well as mold and mildew put children at risk for developing asthma as well as exposure to cigarette smoke.

Unlike many other Western countries, the mortality rate for asthma has steadily risen in the United States over the last two decades. Mortality rates for African American children due to asthma are also far higher than that of other racial groups. For African Americans, the rate of visits to the emergency room is 330 percent higher than their white counterparts. The hospitalization rate is 220 percent higher and the death rate is 190 percent higher. Among Hispanics, Puerto Ricans are disporpotionatly affected by asthma with a disease rate that is 113 percent higher than non-Hispanic Whites and 50 percent higher than non-Hispanic Blacks. Studies have shown that asthma morbidity and mortality are concentrated in inner city neighborhoods characterized by poverty and large minority populations and this affects both genders at all ages. Asthma continues to have an adverse effects on the health of the poor and school attendance rates among poor children. 10.5 million days of school are missed each year due to asthma.

An ectoparasitic infestation is a parasitic disease caused by organisms that live primarily on the surface of the host.

Examples:

- Scabies

- Crab louse (pubic lice)

- Pediculosis (head lice)

- "Lernaeocera branchialis" (cod worm)

The term waterborne disease is reserved largely for infections that predominantly are transmitted through contact with or consumption of infected water. Trivially, many infections may be transmitted by microbes or parasites that accidentally, possibly as a result of exceptional circumstances, have entered the water, but the fact that there might be an occasional freak infection need not mean that it is useful to categorise the resulting disease as "waterborne". Nor is it common practice to refer to diseases such as malaria as "waterborne" just because mosquitoes have aquatic phases in their life cycles, or because treating the water they inhabit happens to be an effective strategy in control of the mosquitoes that are the vectors.

Microorganisms causing diseases that characteristically are waterborne prominently include protozoa and bacteria, many of which are intestinal parasites, or invade the tissues or circulatory system through walls of the digestive tract. Various other waterborne diseases are caused by viruses. (In spite of philosophical difficulties associated with defining viruses as "organisms", it is practical and convenient to regard them as microorganisms in this connection.)

Yet other important classes of water-borne diseases are caused by metazoan parasites. Typical examples include certain Nematoda, that is to say "roundworms". As an example of water-borne Nematode infections, one important waterborne nematodal disease is Dracunculiasis. It is acquired by swallowing water in which certain copepoda occur that act as vectors for the Nematoda. Anyone swallowing a copepod that happens to be infected with Nematode larvae in the genus Dracunculus, becomes liable to infection. The larvae cause guinea worm disease.

Another class of waterborne metazoan pathogens are certain members of the Schistosomatidae, a family of blood flukes. They usually infect victims that make skin contact with the water. Blood flukes are pathogens that cause Schistosomiasis of various forms, more or less seriously affecting hundreds of millions of people worldwide.

Long before modern studies had established the germ theory of disease, or any advanced understanding of the nature of water as a vehicle for transmitting disease, traditional beliefs had cautioned against the consumption of water, rather favouring processed beverages such as beer, wine and tea. For example, in the camel caravans that crossed Central Asia along the Silk Road, the explorer Owen Lattimore noted, "The reason we drank so much tea was because of the bad water. Water alone, unboiled, is never drunk. There is a superstition that it causes blisters on the feet."

Waterborne diseases can have a significant impact on the economy, locally as well as internationally. People who are infected by a waterborne disease are usually confronted with related costs and not seldom with a huge financial burden. This is especially the case in less developed countries. The financial losses are mostly caused by e.g. costs for medical treatment and medication, costs for transport, special food, and by the loss of manpower. Many families must even sell their land to pay for treatment in a proper hospital. On average, a family spends about 10% of the monthly households income per person infected.

Mammals can get parasites from contaminated food or water, bug bites, or sexual contact. Ingestion of contaminated water can produce Giardia infections.

Parasites normally enter the body through the skin or mouth. Close contact with pets can lead to parasite infestation as dogs and cats are host to many parasites.

Other risks that can lead people to acquire parasites are walking barefeet, inadequate disposal of feces, lack of hygiene, close contact with someone carrying specific parasites, and eating undercooked foods, unwashed fruits and vegetables or foods from contaminated regions.

Parasites can also be transferred to their host by the bite of an insect vector, i.e. mosquito, bed bug, fleas.

Deworming treatments in infected children may have some nutritional benefit, as worms are often partially responsible for malnutrition. However, in areas where these infections are common, there is strong evidence that mass deworming campaigns do not have a positive effect on children's average nutritional status, levels of blood haemoglobin, cognitive abilities, performance at school or survival. To achieve health gains in the longer term, improvements in sanitation and hygiene behaviours are also required, together with deworming treatments.

Systemic mycoses due to opportunistic pathogens are infections of patients with immune deficiencies who would otherwise not be infected. Examples of immunocompromised conditions include AIDS, alteration of normal flora by antibiotics, immunosuppressive therapy, and metastatic cancer. Examples of opportunistic mycoses include Candidiasis, Cryptococcosis and Aspergillosis.

Mansonelliasis (or mansonellosis) is the condition of infection by the nematode "Mansonella".

The disease exists in Africa and tropical Americas, spread by biting midges or blackflies. It is usually asymptomatic.

There are 21.4 million people infected with trachoma, of whom 2.2 million are partially blind and 1.2 million are blind. It is found in Africa, Asia, Central and South America, Middle East, and Australia. The disease disproportionately affects women and children. The mortality risk is very low, although multiple re-infections eventually lead to blindness. The symptoms are internally scarred eyelids, followed by eyelids turning inward. Trachoma is caused by a micro-organism that spreads through eye discharges (on hands, cloth, etc.) and by "eye-seeking flies".

It is treated with antibiotics. The only known prevention method is interpersonal hygiene.

Pinworm infection occurs worldwide, and is the most common helminth (i.e., parasitic worm) infection in the United States and Western Europe. In the United States, a study by the Center of Disease Control reported an overall incidence rate of 11.4% among people of all ages. Pinworms are particularly common in children, with prevalence rates in this age group having been reported as high as 61% in India, 50% in England, 39% in Thailand, 37% in Sweden, and 29% in Denmark. Finger sucking has been shown to increase both incidence and relapse rates, and nail biting has been similarly associated. Because it spreads from host to host through contamination, enterobiasis is common among people living in close contact, and tends to occur in all people within a household. The prevalence of pinworms is not associated with gender, nor with any particular social class, race, or culture. Pinworms are an exception to the tenet that intestinal parasites are uncommon in affluent communities.

Systemic mycoses due to primary pathogens originate primarily in the lungs and may spread to many organ systems. Organisms that cause systemic mycoses are inherently virulent. In general primary pathogens that cause systemic mycoses are dimorphic.

Control of this parasite should be directed against reducing the level of

environmental contamination. Treatment of heavily infected individuals is one

way to reduce the source of contamination (one study has estimated that 60% of

the total worm burden resides in less than 10% of the population). Other

obvious methods are to improve access to sanitation, e.g. toilets, but also

convincing people to maintaining them in a clean, functional state, thereby making

them conducive to use.

Pinworm infection cannot be totally prevented under most circumstances. This is due to the prevalence of the parasite and the ease of transmission through soiled night clothes, airborne eggs, contaminated furniture, toys and other objects. Infection may occur in the highest strata of society, where hygiene and nutritional status are typically high. The stigma associated with pinworm infection is hence considered a possible over-emphasis. Counselling is sometimes needed for upset parents that have discovered their children are infected, as they may not realize how prevalent the infection is.

Preventative action revolves around personal hygiene and the cleanliness of the living quarters. The "rate" of reinfection can be reduced through hygienic measures, and this is recommended especially in recurring cases.

The main measures are keeping fingernails short, and washing and scrubbing hands and fingers carefully, especially after defecation and before meals. Under ideal conditions, bed covers, sleeping garments, and hand towels should be changed daily. Simple laundering of clothes and linen disinfects them. Children should wear gloves while asleep, and the bedroom floor should be kept clean. Food should be covered to limit contamination with dust-borne parasite eggs. Household detergents have little effect on the viability of pinworm eggs, and cleaning the bathroom with a damp cloth moistened with an antibacterial agent or bleach will merely spread the still-viable eggs. Similarly, shaking clothes and bed linen will detach and spread the eggs.

"Necator americanus" was first discovered in Brazil and then was found in Texas. Later, it was found to be indigenous in Africa, China, southwest Pacific islands, India, and Southeast Asia. This parasite is a tropical parasite and is the most common species in humans. Roughly 95% of hookworms found in the southern region of the United States are "N. americanus". This parasite is found in humans, but can also be found in pigs and dogs.

Transmission of "N. americanus" infection requires the deposition of egg-containing feces on shady, well-drained soil and is favored by warm, humid (tropical) conditions. Therefore, infections worldwide are usually reported in places where direct contact with contaminated soil occurs.

Areas with the highest prevalence of helminthiasis are tropical and subtropical areas including sub-Saharan Africa, central and east Asia, and the Americas.

Even in areas of high prevalence, the frequency and severity of infection is not uniform within communities or families. A small proportion of community members harbour the majority of worms, and this depends on age. The maximum worm burden is at five to ten years of age, declining rapidly thereafter. Individual predisposition to helminthiasis for people with the same sanitation infrastructure and hygiene behavior is thought to result from differing immunocompetence, nutritional status, and genetic factors. Because individuals are predisposed to a high or a low worm burden, the burden reacquired after successful treatment is proportional to that before treatment.

Prevention can be partially achieved through limiting contact with vectors through the use of DEET and other repellents, but due to the predominantly relatively mild symptoms and the infection being generally asymptomatic, little has formally been done to control the disease.

There are many public health strategies that can drastically limit the transmission of "A. cantonensis" by limiting contact with infected vectors. Vector control may be possible, but has not been very successful in the past. Education to prevent the introduction of rats or snail vectors outside endemic areas is important to limit the spread of the disease. There are no vaccines in development for angiostrongyliasis.

Disseminated strongyloidiasis occurs when patients with chronic strongyloidiasis become immunosuppressed. It presents with abdominal pain, distension, shock, pulmonary and neurologic complications and septicemia, and is potentially fatal. The worms enter the bloodstream from the bowel wall, simultaneously allowing entry of bowel bacteria such as "Escherichia coli". This may cause symptoms such as sepsis (bloodstream infection), and the bacteria may spread to other organs where they may cause localized infection such as meningitis.

Dissemination can occur many decades after the initial infection and has been associated with high dose corticosteroids, organ transplant, HIV, lepromatous leprosy, tertiary syphilis, aplastic anemia, malnutrition, advanced tuberculosis and radiation poisoning. It is often recommended that patients being started on immunosuppression be screened for chronic strongyloidiasis; however, this is often impractical (screen tests are often unavailable) and in developed countries, the prevalence of chronic strongyloidiasis is very small, so screening is usually not cost-effective, except in endemic areas.

It is important to note that there is not necessarily any eosinophilia in the disseminated disease. Absence of eosinophilia may indicate poor prognosis.

"A. cantonensis" and its vectors are endemic to Southeast Asia and the Pacific Basin. The infection is becoming increasingly important as globalization allows it to spread to more and more locations, and as more travelers encounter the parasites. The parasites probably travel effectively through rats traveling as stowaways on ships, and through the introduction of snail vectors outside endemic areas.

Although mostly found in Asia and the Pacific where asymptomatic infection can be as high as 88%, human cases have been reported in the Caribbean, where as much as 25% of the population may be infected. In the United States, cases have been reported in Hawaii, which is in the endemic area [5]. The infection is now endemic in wildlife and a few human cases have also been reported in areas where the parasite was not originally endemic, such as New Orleans and Egypt.

The disease has also arrived in Brazil, where there were 34 confirmed cases from 2006 to 2014, including one death. The giant African land snail, which can be a vector of the parasite, has been introduced to Brazil as an invasive species and is spreading the disease. There may be more undiagnosed cases, as Brazilian physicians are not familiar with the eosinophilic meningitis associated to angiostrongyliasis and misdiagnose it as bacterial or viral.

Latest estimates indicate that the total annual death toll which is directly attributable is as high as 135,000. The death toll due to the malnutrition link is likely to be much higher.

Secondary bacterial infection is common among patients with filariasis. Compromised immune function due to lymphatic damage in addition to lymph node ulcerations and abscesses exposure and impaired circulation due to elephantiasis can cause secondary bacterial or fungal infection. Elephantiasis, in addition to the physical burden of a swollen limb, can be a severely dehabilitating condition given bacterial infection. Part of the WHO's "Strategy to Eliminate Lymphatic Filariasis" targets hygiene promotion programs in order to alleviate the suffering of affected individuals (see Prevention Strategies).

However, clinical manifestations of infection are variable and depend on several factors, including host immune system, infectious dose, and parasite strain differences. Most infections appear asymptomatic, yet vary from individual to individual. Individuals living in endemic areas with microfilaremia may never present with overt symptoms, whereas in other cases, only a few worms can exacerbate a severe inflammatory response.

The development of the disease in humans, however, is not well understood. Adults typically develop worse symptoms, given the long exposure time required for infection. Infection may occur during childhood, but the disease appears to take many years to manifest. The incubation period for infection ranges from 1 month to 2 years and typically microfilariae appear before overt symptoms. Lymphedema can develop within six months and development of elephantiasis has been reported within a year of infection among refugees, who are more immunologically naive. Men tend to develop worse symptoms than women.

Education, improved sanitation, and controlled disposal of human feces are critical for prevention. Nonetheless, wearing shoes in endemic areas helps reduce the prevalence of infection.

Avoid ingestion of raw freshwater fish. Adequate cooking or freezing of freshwater fish will kill the encysted fish tapeworm larvae. Also, because human feces is an important mechanism for spreading eggs, proper disposal of sewage can cut down on infection of fish and thus of humans.