Can offspring sex ratios help to explain the endocrine effects of toxoplasmosis infection on human behaviour?

James, William H.; Grech, Victor

doi:10.1016/j.earlhumdev.2018.06.001

Cited by 2 publications

(2 citation statements)

References 37 publications

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“…However, its evolutionary purpose may be to ensure that the healthiest females survive to ensure effective reproductive capabilities. In times of stress, where the livebirth M/F ratio is reduced, the mechanism may involve either reduced female wastage or increased male wastage during the first trimester (28). Physical or psychological stressor situations have been associated with an increased risk of miscarriages (29), suggesting that the most likely mechanism in play is more likely to be an increase in first trimester male wastage rather than a protective mechanism to reduce female wastage and the mechanism for this may be the observed raised progesterone and cortisol during times of stress (30).…”

Section: Discussionmentioning

confidence: 99%

Stressor Effects on Sex Ratios and Births in the Maltese Population during the First Half of the 20th Century

Venture

Grech

2022

Acta Med. (Hradec Kralove, Czech Repub.)

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Background: The sex ratio at birth (male/total = M/F) is expected to approximate 0.515. Stress is known to reduce livebirth M/F. In the first half of the 20th century, Malta was stressed by two World Wars. Objectives: This study was carried out in order to analyse changes in reproductive performance and M/F of stillbirths and livebirths in Malta during this period. Methods: Livebirth and stillbirth data (1910–1951) were obtained from official published Maltese government reports. Stillbirths were defined as any antenatal loss after 28 weeks of gestation. Results: This analysis studied 347,562 live and 11,662 stillbirths. For 1919–1951, M/F at birth was 0.517, stillbirth M/F was 0.664, implying 28/40 M/F = 0.522. Assuming conceptional M/F = 0.5, estimated M/F for fetal wastage before 28 weeks was approximately 0.434. There was a decrease in the overall birth rate starting after 1911 to 1921, more marked for 1941–1943 followed by an overshoot in 1943–48. There was a statistically significant drop in M/F livebirths during the periods 1916–21 and 1934–45. Stillbirths decreased significantly after 1935 (M>F). A stillbirth M/F drop in 1937–45 and rise in 1946–51 were statistically significant. Conclusions: Birth rate drops in both wars were ascribed to conscription, adverse living conditions and decreased fertility from nutritional restrictions. Both conflicts resulted in short post-war baby booms. The decrease in stillbirths is attributed to increase in antenatal attendances, hospital births and special food rations for pregnant women. The M/F observations suggest that the selective survival of both healthier female and male foetuses is favoured during times of stress.

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Section: Discussionmentioning

confidence: 99%

Stressor Effects on Sex Ratios and Births in the Maltese Population during the First Half of the 20th Century

Venture

Grech

2022

Acta Med. (Hradec Kralove, Czech Repub.)

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“…Manipulation of host behavior by the parasite makes infected male rats more attractive to females, also, uninfected females spend more time near infected males and give them more fertility opportunities, thus creating more ways of sexual transmission by the parasite itself, humans infected with the Toxoplasma parasite exhibit a variety of abnormal behaviors, from suicide and depression to stuttering, these behaviors are seen as so serious that they constitute a public health problem, it is not clear whether the parasite is a cause or merely a sign of these behaviors, but there is evidence for both, some of these behaviors are linked to changes in steroid hormones, namely estrogen in women and testosterone in men (James & Grech, 2018).…”

Section: Alzheimer's Patients Infected With Toxoplasma Gondii By Gendermentioning

confidence: 99%

Toxoplasma Gondii a risk factor for Alzheimer’s disease infection, in Al-Diwaniyah Governorate, Iraq

Al-Shabani¹,

Al-Waaly²

2022

ijhs

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The results of the serological examination of 35 patients with Alzheimer's disease showed that 21 of them were infected with Toxoplasma Gondii by 60% for the period from the beginning of February until the end of May 2022, the high odds ratio value (OR = 7.87) showed the role of Toxoplasma infection in causing Alzheimer's disease, and there was no effect of age and gender on infection with Toxoplasma parasite in Alzheimer's patients.

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Can offspring sex ratios help to explain the endocrine effects of toxoplasmosis infection on human behaviour?

Cited by 2 publications

References 37 publications

Stressor Effects on Sex Ratios and Births in the Maltese Population during the First Half of the 20th Century

Stressor Effects on Sex Ratios and Births in the Maltese Population during the First Half of the 20th Century

Toxoplasma Gondii a risk factor for Alzheimer’s disease infection, in Al-Diwaniyah Governorate, Iraq

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