Cooperation in organisms, whether bacteria or primates, has been a difficulty for evolutionary theory since Darwin. On the assumption that interactions between pairs of individuals occur on a probabilistic basis, a model is developed based on the concept of an evolutionarily stable strategy in the context of the Prisoner's Dilemma game. Deductions from the model, and the results of a computer tournament show how cooperation based on reciprocity can get started in an asocial world, can thrive while interacting with a wide range of other strategies, and can resist invasion once fully established. Potential applications include specific aspects of territoriality, mating, and disease.

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The Evolution of Cooperation

Several infectious agents are considered to be causes of cancer in humans. The fraction of the different types of cancer, and of all cancers worldwide and in different regions, has been estimated using several methods; primarily by reviewing the evidence for the strength of the association (relative risk) and the prevalence of infection in different world areas. The estimated total of infection-attributable cancer in the year 2002 is 1.9 million cases, or 17.8% of the global cancer burden. The principal agents are the bacterium Helicobacter pylori (5.5% of all cancer), the human papilloma viruses (5.2%), the hepatitis B and C viruses (4.9%), Epstein-Barr virus (1%), human immunodeficiency virus (HIV) together with the human herpes virus 8 (0.9%). Relatively less important causes of cancer are the schistosomes (0.1%), human T-cell lymphotropic virus type I (0.03%) and the liver flukes (0.02%). There would be 26.3% fewer cancers in developing countries (1.5 million cases per year) and 7.7% in developed countries (390,000 cases) if these infectious diseases were prevented. The attributable fraction at the specific sites varies from 100% of cervix cancers attributable to the papilloma viruses to a tiny proportion (0.4%) of liver cancers (worldwide) caused by liver flukes.

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The global health burden of infection-associated cancers in the year 2002.

Epstein-Barr virus.

Kaposi's sarcoma-associated herpesvirus-like DNA sequences in multicentric Castleman's disease

ContextEpidemiological and experimental evidence suggests that high levels of vitamin D, a potent immunomodulator, may decrease the risk of multiple sclerosis. There are no prospective studies addressing this hypothesis.ObjectiveTo examine whether levels of 25-hydroxyvitamin D are associated with risk of multiple sclerosis.Design, Setting, and ParticipantsProspective, nested case-control study among more than 7 million US military personnel who have serum samples stored in the Department of Defense Serum Repository. Multiple sclerosis cases were identified through Army and Navy physical disability databases for 1992 through 2004, and diagnoses were confirmed by medical record review. Each case (n = 257) was matched to 2 controls by age, sex, race/ethnicity, and dates of blood collection. Vitamin D status was estimated by averaging 25-hydroxyvitamin D levels of 2 or more serum samples collected before the date of initial multiple sclerosis symptoms.Main Outcome MeasuresOdds ratios of multiple sclerosis associated with continuous or categorical levels (quantiles or a priori–defined categories) of serum 25-hydroxyvitamin D within each racial/ethnic group.ResultsAmong whites (148 cases, 296 controls), the risk of multiple sclerosis significantly decreased with increasing levels of 25-hydroxyvitamin D (odds ratio [OR] for a 50-nmol/L increase in 25-hydroxyvitamin D, 0.59; 95% confidence interval, 0.36-0.97). In categorical analyses using the lowest quintile (<63.3 nmol/L) as the reference, the ORs for each subsequent quintile were 0.57, 0.57, 0.74, and 0.38 (P = .02 for trend across quintiles). Only the OR for the highest quintile, corresponding to 25-hydroxyvitamin D levels higher than 99.1 nmol/L, was significantly different from 1.00 (OR, 0.38; 95% confidence interval, 0.19-0.75; P = .006). The inverse relation with multiple sclerosis risk was particularly strong for 25-hydroxyvitamin D levels measured before age 20 years. Among blacks and Hispanics (109 cases, 218 controls), who had lower 25-hydroxyvitamin D levels than whites, no significant associations between vitamin D and multiple sclerosis risk were found.ConclusionThe results of our study suggest that high circulating levels of vitamin D are associated with a lower risk of multiple sclerosis.

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Serum 25-hydroxyvitamin D levels and risk of multiple sclerosis

Background The acute chest syndrome is the leading cause of death among patients with sickle cell disease. Since its cause is largely unknown, therapy is supportive. Pilot studies with improved diagnostic techniques suggest that infection and fat embolism are underdiagnosed in patients with the syndrome. Methods In a 30-center study, we analyzed 671 episodes of the acute chest syndrome in 538 patients with sickle cell disease to determine the cause, outcome, and response to therapy. We evaluated a treatment protocol that included matched transfusions, bronchodilators, and bronchoscopy. Samples of blood and respiratory tract secretions were sent to central laboratories for antibody testing, culture, DNA testing, and histopathological analyses. Results Nearly half the patients were initially admitted for another reason, mainly pain. When the acute chest syndrome was diagnosed, patients had hypoxia, decreasing hemoglobin values, and progressive multilobar pneumonia. The mean length of hospitalization was 10....

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Causes and Outcomes of the Acute Chest Syndrome in Sickle Cell Disease

We conducted a study to identify the viruses in tissue specimens of oral "hairy" leukoplakia, a lesion that is found in immunosuppressed male homosexuals and that is associated with the subsequent development of the acquired immunodeficiency syndrome. When stained for papillomavirus core antigen, 49 of 67 biopsy specimens (73 per cent) yielded positive results in epithelial-cell nuclei. Electron microscopy showed papillomavirus-like particles in all of 25 specimens, and the herpes-type virus described in a previous report was seen in 23 of the 25 specimens. Three specimens had both types of particle in the same individual epithelial cells. Immunofluorescence for herpes simplex virus, varicella-zoster virus, and cytomegalovirus gave negative results in all cases, but 19 of 20 specimens showed intense nuclear staining in epithelial cells for the viral capsid antigen of Epstein-Barr virus (EBV). DNA hybridization using EBV probes in Southern blots demonstrated EBV DNA in all of 13 specimens and found 200 or more viral DNA molecules per cellular genome in 11 of the 13. The whole EBV genome was also demonstrated in the specimens and found to be in linear virion form. We conclude that EBV replicates within the epithelial cells in hairy leukoplakia.

Replication of Epstein–Barr Virus within the Epithelial Cells of Oral Hairy Leukoplakia, an AIDS-Associated Lesion

Herpes-like sequences in HIV-infected and uninfected Kaposi's sarcoma patients

https://www.thelancet.com/pdfs/journals/lancet/PIIS0140-6736(96)03240-0.pdf

Antibodies to human herpesvirus type 8 in the general population and in Kaposi's sarcoma patients

ContextEpidemiological studies suggest an association between infection with
Epstein-Barr virus (EBV) and risk of multiple sclerosis (MS).ObjectiveTo determine whether elevation in serum antibody titers to EBV viral
capsid antigen (VCA), nuclear antigens (EBNA, EBNA-1, and EBNA-2), and diffuse
and restricted early antigen (EA-D and EA-R) as well as to cytomegalovirus
(CMV) precede the occurrence of MS.Design, Setting, and SubjectsProspective, nested case-control study. Of 62 439 women participating
in the Nurses' Health Study (aged 30-55 years in 1976) and Nurses' Health
Study II (aged 25-42 years in 1989) who gave blood samples in 1989-1990 and
1996-1999, respectively, and were followed up through 1999, 144 women with
definite or probable MS and 288 healthy age-matched controls were included
in the analysis.Main Outcome MeasureSerum antibody titers to the specific EBV and CMV antigens, compared
between cases and controls.ResultsWe documented 18 cases of MS with blood collected before disease onset.
Compared with their matched controls, these women had higher serum geometric
mean titers (GMTs) of antibodies to EBV but not CMV. Elevations were significant
for antibodies to EBNA-1 (GMT, 515 vs 203; P = .03),
EBNA-2 (GMT, 91 vs 40; P = .01), and EA-D (15.9 vs
5.9; P = .04). The strongest association was found
for antibodies to EBNA-2; a 4-fold difference in titers was associated with
a relative risk (RR) of MS of 3.9 (95% confidence interval [CI], 1.1-13.7).
The corresponding RRs were 1.6 (95% CI, 0.7-3.7) for VCA, 2.5 (95% CI, 1.0-6.3)
for EBNA, 1.8 (95% CI, 1.0-3.1) for EA-D, and 1.0 (95% CI, 0.6-1.7) for CMV.
Significant but generally weaker elevations in anti-EBV antibodies were also
found in analyses of 126 cases of MS with blood collected after disease onset
and their matched controls.ConclusionsOur results support a role of EBV in the etiology of MS.

https://jamanetwork.com/journals/jama/articlepdf/194503/JOC11194.pdf

Evelyne T. Lennette

Papers

Causes and Outcomes of the Acute Chest Syndrome in Sickle Cell Disease

Replication of Epstein–Barr Virus within the Epithelial Cells of Oral Hairy Leukoplakia, an AIDS-Associated Lesion

Herpes-like sequences in HIV-infected and uninfected Kaposi's sarcoma patients

Antibodies to human herpesvirus type 8 in the general population and in Kaposi's sarcoma patients

Epstein-Barr Virus Antibodies and Risk of Multiple Sclerosis: A Prospective Study