To date, CKDu (MeN) causes remain undetermined and debatable; nevertheless the number of cases could lead to the application of a precautionary principles from a humanitarian perspective. Due to the fact that the Mesoamerican nephropathy is regarded as a multifactorial disease the experimental design of comparative study should take following logical setting into account.

Multifactorial problem. Assume that a disease is definitely caused by A,B,C. The disease will develop if at least 2 risk factors are present in a certain region.

- formula_1 no prevalence of disease in region 1

- A no prevalence of disease in region 2

- B no prevalence of disease in region 3

- C no prevalence of disease in region 4

- A,B prevalence of disease in region 5

- B,C prevalence of disease in region 6

- C,A prevalence of disease in region 7

- A,B,C prevalence of disease in region 8

Removing the risk factor A in the experimental group in comparison to control group will lead to changes in the outbreak of the disease in only 2 of 8 combinatorically possible regions, even if we define A as a relevant risk factor in this theoretical setting. The same is true if the experimental design adds in a comparative study the risk factor A to the regions in the experimental group in comparison to the control group.

If the difference in experimental and control are 2 risk factors (adding or removing two risk factor e.g. A,B in the control group), then 4 regions will show a differences in prevalence of the disease, with the disadvantage that the experimental design cannot clarify if one or both risk factors A and B are contributing to the progression and prevalence of the disease.

Beside this logical analysis of a multifactorial setting there is space for further investigation, e.g.: Leptospirosis has been suggested as a possible contributing factor and oceanic nephrotoxic algae or agents have also been brought to the chart of possibilities as a culprit for this unusual form of kidney damage..

Assessment of the mentioned risk factors and their possible synergism will depend on more and better research.

Dyschromatosis symmetrica hereditaria (also known as "reticulate acropigmentation of Dohi", and "symmetrical dyschromatosis of the extremities") is a rare autosomally inherited dermatosis. It is characterized by progressively pigmented and depigmented macules, often mixed in a reticulate pattern, concentrated on the dorsal extremities. It presents primarily in the Japanese, but has also been found to affect individuals from Europe, India and the Caribbean.

This disease is caused by mutation in the double stranded RNA specific adenosine deaminase (ADAR1) gene. This gene is located on the long arm of chromosome 1 (1q21).

Adding elements to the debate, another recent study from Sri Lanka, where a similar and apparently new form of CKDu has become a serious public health concern too, suggests chronic synergestic exposure to multiple pesticide residues and heavy metal could be the main causal factor. The authors hypothesize that “Agrochemicals are the essential factor for the disease“. Dr. Channa Jayasumana, a Sri Lankan researcher, member of the medical faculty of Rajarata University, has been a leading supporter of the pesticide hypothesis, always in connection to hard water consumption. He has said that research conducted by his university found that “pesticides and chemical fertilizers were responsible for the spike in kidney diseases”, Further he points out heat stress and dehydration is an important aggravating factor of the disease.

There have not been sufficient studies conducted to make conclusive statements about prevalence nor who tends to suffer EHS. One study found that 13.5% of a sample of undergrads reported at least one episode over the course of their lives, with higher rates in those also suffering from sleep paralysis.

Dyskeratosis congenita (DKC), also called Zinsser-Cole-Engman syndrome, is a rare progressive congenital disorder with a highly variable phenotype. The entity was classically defined by the triad of abnormal skin pigmentation, nail , and leukoplakia of the oral mucosa, but these components do not always occur. DKC is characterized by short telomeres. Some of the manifestations resemble premature aging (similar to progeria). The disease initially mainly affects the skin, but a major consequence is progressive bone marrow failure which occurs in over 80%, causing early mortality.

As of 2014, no clinical trials had been conducted to determine what treatments are safe and effective; a few case reports had been published describing treatment of small numbers of people (two to twelve per report) with clomipramine, flunarizine, nifedipine, topiramate, carbamazepine, methylphenidate. Studies suggest that education and reassurance can reduce the frequency of EHS episodes. There is some evidence that individuals with EHS rarely report episodes to medical professionals.

In terms of frequency, is estimated at 2 per 100,000, it has identified in different regions of the world. Some clusters of certain types of autosomal dominant cerebellar ataxia reach a prevalence of 5 per 100,000.

DKC can be characterized by cutaneous pigmentation, premature graying, of the nails, leukoplakia of the oral mucosa, continuous lacrimation due to atresia of the lacrimal ducts, often thrombocytopenia, anemia, testicular atrophy in the male carriers, and predisposition to cancer. Many of these symptoms are characteristic of geriatrics, and those carrying the more serious forms of the disease often have significantly shortened lifespans.

Long-term nonprogressors (LTNPs), sometimes also called "elite controllers", are individuals infected with HIV, who maintain a CD4 count greater than 500 without antiretroviral therapy with a detectable viral load. Many of these patients have been HIV positive for 30 years without progressing to the point of needing to take medication in order not to develop AIDS. They have been the subject of a great deal of research, since an understanding of their ability to control HIV infection may lead to the development of immune therapies or a therapeutic vaccine. The classification "Long-term non-progressor" is not permanent, because some patients in this category have gone on to develop AIDS.

Long-term nonprogressors typically have viral loads under 10,000 copies RNA/ml blood, do not take antiretrovirals, and have CD4+ counts within the normal range. Most people with HIV not on medication have viral loads which are much higher.

It is estimated that around 1 in 300 people with HIV are long-term nonprogressors. Without the symptoms of AIDS, many LTNP patients may not know they are infected.

Genetic traits that confer greater resistance or more robust immune response to HIV are thought to explain why LTNP patients are able to live much longer with HIV than patients who are not LTNP. Some LTNP are infected with a weakened or inactive form of HIV, but it is now known that many LTNP patients carry a fully virulent form of the virus. Genetic traits that may affect progression include:

- Gene mutation. A mutation in the FUT2 gene affects the progression of HIV-1 infection. 20% of Europeans who have that mutation are called "non secretor" because of their absence of a certain type of antigen that also provides strong resistance against norovirus.

- Mitochondrial DNA. Different mitochondrial DNA haplotypes in humans may increase or decrease rates of AIDS progression. Haplotypes associated with more loosely coupled mitochondrial respiration, with reduced ATP and ROS generation, have been associated with faster progression and vice versa.

- Receptor mutations. A low percentage of long-term nonprogressors have been shown to have inherited mutations of the CCR5 receptor of T cell lymphocytes. HIV uses CCR5 to enter these cells. It is believed that the Δ32 (delta 32) variant of CCR5 impairs HIV ability to infect cells and cause disease. An understanding of this mechanism led to the development of a class of HIV medicines, the entry inhibitors. The presence of this mutation, however, is not a unifying theme among LTNPs and is observed in an exceedingly small number of these patients.

- HLA type has also been correlated with long-term non-progressor cohorts. In particular, strong correlations have been found between possessing the class 1 HLA-B*5701, HLA-B*5703, and/or HLA-B*2705 alleles and ability to exert control over HIV.

- Antibody production. All individuals with HIV make antibodies against the virus. In most patients, broadly neutralizing antibodies do not emerge until approximately 2–4 years after the initial infection. At this point, the latent reservoir has already been established and the presence of broadly neutralizing antibodies is not enough to prevent disease progression. In some rare patients, these antibodies emerge earlier and can result in a delayed disease course. These patients, however, are not typically classified as LTNPs, but rather as slow progressors, who will eventually develop AIDS. Induction of broadly neutralizing antibodies in healthy individuals is a potential strategy for a preventive HIV vaccine, as is the elicitation of these antibodies through rationally designed immunogens. Direct production of these antibodies in somatic tissue through plasmid transfection also pose a viable method for making these antibodies available in a large number of humans.

- APOBEC3G protein production. In a small number of people infected with HIV, the virus is naturally suppressed without medical treatment. These people may carry high quantities of a protein called APOBEC3G that disrupts viral replication in cells. APOBEC3G, or "A3" for short, is a protein that sabotages reverse transcription, the process HIV relies on for its replication. This process involves the virus transcribing its singe-stranded RNA genome into double-stranded DNA that is incorporated into the cell's genome. A3 usually stops dormant viruses in the human genome, called endogenous retroviruses, from reawakening and causing infections.

In virology, defective interfering particles (DIPs), also known as defective interfering viruses, are spontaneously generated virus mutants in which a critical portion of the particle's genome has been lost due to defective replication. DIPs are derived from and associated with their parent virus, and particles are classed as DIPs if they are rendered non-infectious due to at least one essential gene of the virus being lost or severely damaged as a result of the defection. A DIP can usually still penetrate host cells, but requires another fully functional virus particle (the 'helper' virus) to co-infect a cell with it, in order to provide the lost factors. The existence of DIPs has been known about for decades, and they can occur within nearly every class of both DNA and RNA viruses.

Suudu (Tamil, pronounced ) is a culture-specific syndrome of painful urination and pelvic "heat" familiar in South India, especially in the Tamil culture. It occurs in males and females. It is popularly attributed to an increase in the "inner heat" of the body often due to dehydration. It is usually treated by the following.

1. applying a few drops of sesame oil or castor oil in the navel and the pelvic region

2. having an oil massage followed by a warm water bath

3. intake of fenugreek seeds soaked overnight in water

The problem has also been known to exist in other parts of South India and the methods of treatment are also similar.

Inadequate nutrition or the consumption of tainted food are suspected. Both IgG and IgM autoantibodies to platelet and to glycoprotein IIb/IIIa is found in majority of patients.

X-linked intellectual disability (previously known as X-linked mental retardation) refers to forms of intellectual disability which are specifically associated with X-linked recessive inheritance.

As with most X-linked disorders, males are more heavily affected than females. Females with one affected X chromosome and one normal X chromosome tend to have milder symptoms.

Unlike many other types of intellectual disability, the genetics of these conditions are relatively well understood. It has been estimated there are ~200 genes involved in this syndrome; of these ~100 have been identified.

X-linked intellectual disability accounts for ~16% of all cases of intellectual disability in males.

Coconut Cadang Cadang Viroid (CCCVd) can be confused with another viroid called Coconut Tinangaja Viroid (CTiVd). That is because both viroids have 64% of their sequence of nucleotides in common. They both affect coconut palm, and infected plants have similar symptoms: spots on the leaves reduced top, yellow palms and even death.

There are few differences between both viroids in the effects caused on fruit: CTiVd causes small nuts, while CCCVd causes round and reduced nuts. Moreover, CTiVd has 254 nucleotides of length, while CCCVd has 246.

Numerous factors have been suggested and linked to a higher risk of acquiring the infection, inclusive of malnutrition, vitamin A deficiency, absence of breastfeeding during the early stages of life, environmental pollution and overcrowding.

Several X-linked syndromes include intellectual disability as part of the presentation. These include:

- Coffin–Lowry syndrome

- MASA syndrome

- MECP2 duplication syndrome

- X-linked alpha thalassemia mental retardation syndrome

- mental retardation and microcephaly with pontine and cerebellar hypoplasia

Coconut cadang-cadang disease has no treatment yet. However, chemotherapy with antibiotics has been tried with tetracycline solutions; antibiotics failed trying to alter progress of the disease since they had no significant effect on any of the studied parameters. When the treated plants were at the early stage, tetracycline injections failed to prevent the progression of the palms to more advanced stages, nor did they affect significantly the mean number of spathes or nuts. Penicillin treatment had no apparent improvement either.

Control strategies are elimination of reservoir species, vector control, mild strain protection and breeding for host resistance. Eradication of diseased plants is usually performed to minimize spread but is of dubious efficacy due to the difficulties of early diagnosis as the virus etiology remains unknown and the one discovered are the three main stages in the disease development.

Epidermolytic ichthyosis (EI), (also known as "epidermolytic hyperkeratosis (EHK)", "bullous congenital ichthyosiform erythroderma (BCIE), bullous ichthyosiform erythroderma, or bullous congenital ichthyosiform erythroderma Brocq) is a rare and severe form of ichthyosis this skin disease affects around 1 in 300,000 people.

It involves the clumping of keratin filaments.

Mortality caused by HPIVs in developed regions of the world remains rare. Where mortality has occurred, it is principally in the three core risk groups (very young, elderly and immuno-compromised). Long term changes can however be associated with airway remodelling and are believed to be a significant cause of morbidity. The exact associations between HPIVs and diseases such as chronic obstructive pulmonary disease (COPD) are still being investigated.

In developing regions of the world, the highest risk group in terms of mortality remains pre-school children. Mortality may be as a consequence of primary viral infection or secondary problems such as bacterial infection. Predispositions, such as malnutrition and other deficiencies may further elevate the chances of mortality associated with infection.

Overall, LRI's cause approximately 25–30% of total deaths in pre-school children in the developing world. HPIVs is believed to be associated with 10% of all LRI cases, thus remaining a significant cause of mortality.

Onyalai is an acquired form of immune thrombocytopenia which differs clinically, epidemiologically and immunologically from idiopathic thrombocytopenic purpura.

AIED is generally caused by either antibodies or immune cells that cause damage to the inner ear. There are several theories that propose a cause of AIED:

- Bystander damage – Physical damage to the inner ear may lead to cytokine release that signals for an immune response. This may be a component of the "attack/remission cycle" of Meniere's disease.

- Cross-reactions – Accidental damage of the inner ear by antibodies or T-cells that recognize an inner ear antigen that is similar to a bacterial or viral antigen

- Genetic factors – Predisposition to developing an autoimmune disorder based on genes inherited

- Intolerance – The immune system may not be aware of all the antigens present in the inner ear until physical damage releases some of these antigens. As a result, the immune system treats these unfamiliar antigens as foreign and mounts an immune response.

Currently, the cross-reactions theory appears to be the favored mechanism of AIED pathogenesis.

Flacherie (literally: "flaccidness") is a disease of silkworms, caused by silkworms eating infected or contaminated mulberry leaves. Flacherie infected silkworms look weak and can die from this disease. Silkworm larvae that are about to die from Flacherie are a dark brown.

There are two kinds of flacherie: essentially, infectious (viral) flacherie and noninfectious ("bouffee") flacherie. Both are technically a lethal diarrhea.

Bouffée flacherie is caused by heat waves ("bouffée" means "sudden heat spell" in French).

Viral flacherie is ultimately caused by infection with "Bombyx mori" infectious flacherie virus (BmIFV, Iflaviridae), "Bombyx mori" densovirus (BmDNV, Parvoviridae) or "Bombyx mori" cypovirus 1 (BmCPV-1, Reoviridae). This either alone or in combination with bacterial infection destroys the gut tissue. Bacterial pathogens contributing to infectious flaccherie are "Serratia marcescens", and species of "Streptococcus" and "Staphylococcus" in the form known as thatte roga.

Louis Pasteur, who began his studies on silkworm diseases in 1865, was the first one able to recognize that mortality due to viral flacherie was caused by infection. (Priority, however, was claimed by Antoine Béchamp.) Richard Gordon described the discovery: "The French silk industry was meanwhile plummeting from a 130 million to an 8 million francs annual income, because the silkworms had all caught "pébrine," black pepper disease…He [Pasteur] went south from Paris to Alais, and rewarded them by discovering the silkworm epidemic to be inflicted by some sort of living microbe…Pasteur threw in another disease, "flâcherie," silkworm diarrhoea. The cures for both were culling the insects which showed the peppery spots — the peasants bottled the silkworm moths in brandy, for display to the experts — and rigorous hygiene of the mulberry leaf."

A 1992 study of 163 affected persons found that most patients had no other medical problems and most manage to lead a relatively normal life.

Patients infected in solid organ transplants have developed a severe fatal illness, starting within weeks of the transplant. In all reported cases, the initial symptoms included fever, lethargy, anorexia and leukopenia, and quickly progressed to multisystem organ failure, hepatic insufficiency or severe hepatitis, dysfunction of the transplanted organ, coagulopathy, hypoxia, multiple bacteremias and shock. Localized rash and diarrhea were also seen in some patients. Nearly all cases have been fatal.

In May 2005, four solid-organ transplant recipients contracted an illness that was later diagnosed as lymphocytic choriomeningitis. All received organs from a common donor, and within a month of transplantation, three of the four recipients had died as a result of the viral infection. Epidemiologic investigation traced the source to a pet hamster that the organ donor had recently purchased from a Rhode Island pet store. Similar cases occurred in Massachusetts in 2008, and Australia in 2013. Currently, there is not a LCMV infection test that is approved by the Food and Drug Administration for organ donor screening. The "Morbidity and Mortality Weekly Report" advises health-care providers to "consider LCMV infection in patients with aseptic meningitis and encephalitis and in organ transplant recipients with unexplained fever, hepatitis, or multisystem organ failure."