Table 3.

Major parasites infecting men and their consequences on male fertility

Parasites	Infected genital organs	Damage to genital tract organs	Causes of male infertility
Acanthamoeba spp.	• Prostate [204] • Testis [205]	• Necrotic lesions in testicular parenchyma [205] • Fibrin thrombosis of testicular small arteries and capillaries [205]	• Not directly reported
Entamoeba histolytica	• Testis [206] • Epididymis [206] • Seminal vesicles and fluid [207] • Prostate [208] • Penis [209]	• Vacuolation of germ cells [206] • Increased and edematous testicular stroma [206] • Erosion of epididymal duct wall by the parasite [206] • Sperm and fibrin clots in epididymal lumen [206] •Dilation of epididymal tubules [206] • Enlarged and tender seminal vesicles [206, 207] • Prostatitis [208] • Ulcers on the prepuce [209]	• Not directly reported however: • Aspermatogenesis in many seminiferous tubules [206]
Leishmania spp.	• Penis (cutaneous form) [210–214] • Testicular macrophages? (visceral form) [215]	• Suspected damage to seminiferous tubules [215]	• Dysfunction of the pituitary–gonadal axis [215] • Suspected deregulation of spermatogenesis [215]
Plasmodium spp.	• Testis [216, 217]	• Testicular pain and swelling [216, 217]	• Oligozoospermia, necrozoospermia, temporary azoospermia [218] • Lower testosterone levels [219]
Schistosoma spp.	• Prostate [220, 221] • Seminal vesicles and semen [220, 221] • Testis [220, 221] • Epididymis [220, 221]	• Dyspareunia [220] • Prostatitis [220] • Haematospermia due to ulceration of seminal vesicule mucosal lining [220] • Hydrocele [220] • Orchitis [220] • Epididymitis [220]	• Oligozoospermia, azoospermia [220, 221] • Poor sperm motility and viability [220–222]
Toxoplasma gondii	• Testis [223–227] • Prostate [228]	• Epididymitis [224] • Orchitis and testicular necrosis [223, 225–227] • Testicular granulomas [224]	• Not directly reported however: • Lower sperm concentration and motility [229] • Anti-sperm antibodies [230]
Trichomonas vaginalis	• Urethra [231] • Prostate [231–233] • Testis [234, 235] • Epididymis [233, 236]	• Urethritis [231] • Prostatitis [231–233] • Orchitis [234] • Atrophic testes [234, 235] • Epididymitis [233, 236]	• Low serum testosterone [234, 235] • Hypogonadism and oligoasthenoteratozoospermia [234] • Azoospermia [235, 236] • Decreased spermatozoa motility and morphological alterations [237]
Trypanosoma brucei	• No direct organ infection described	• Atrophy of seminiferous tubules [238] • Reduction of testicular volume [239]	• Testicular hypogonadism [240, 241] • Lower testosterone plasma levels [240–242] • Impotency [239, 241–243]
Trypanosoma cruzi	• Testis [244–246]	• Epididymo-orchitis [244] • Hypoplasia of germ cells [245, 246] • Maturation arrest of germ cells [245, 246] • Degeneration of Leydig cells [245, 246]	• Not directly reported however: • Loss of libido and impotency [245, 246] • Oligozoospermia to azoospermia in chronically infected men [245]
Wuchereria bancrofti	• Testis [247, 248]	• Hydrocele [249] • Epididymo-orchitis [247, 249] • Atrophy of seminiferous tubules [250] • Recurrent scrotal pain and swelling [251] • Elephantiasis [250]	• Oligozoospermia and non-motile spermatozoa [249] • Azoospermia [250]

This table summarizes the organ location of the parasites that are known to affect male fertility. It specifies the parasite location in the male genital tract, the damage to these organs and the proven or possible causes of male infertility as reported in the literature. It is of note that even if no direct infection of the genital tract is mentioned in the literature, Trypanosoma brucei is clearly associated with possible causes of infertility

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