Post-testicular causes
Post-testicular factors decrease male fertility due to conditions that affect the male genital system after testicular sperm production and include defects of the genital tract as well as problems in ejaculation:
Vas deferens obstruction
Lack of Vas deferens, often related to genetic markers for cystic fibrosis
Infection, e.g. prostatitis, male accessory gland infection
Retrograde ejaculation
Ejaculatory duct obstruction
Hypospadias
Impotence

Diagnostic evaluations
The diagnosis of infertility begins with a medical history and physical exam by a physician, physician assistant, or nurse practitioner. Typically two separate semen analyses will be required. The provider may order blood tests to look for hormone imbalances, medical conditions, or genetic issues. Medical history
The history should include prior testicular or penile insults (torsion, cryptorchidism, trauma), infections (mumps orchitis, epididymitis), environmental factors, excessive heat, radiation, medications, and drug use (anabolic steroids, alcohol, smoking).Sexual habits, frequency and timing of intercourse, use of lubricants, and each partners previous fertility experiences are important.Loss of libido and headaches or visual disturbances may indicate a pituitary tumor.The past medical or surgical history may reveal thyroid or liver disease (abnormalities of spermatogenesis), diabetic neuropathy (retrograde ejaculation), radical pelvic or retroperitoneal surgery (absent seminal emission secondary to sympathetic nerve injury), or hernia repair (damage to the vas deferens or testicular blood supply).A family history may reveal genetic problems. Physical examination
Usually, the patient disrobes completely and puts on a gown. The physician, physician assistant, or nurse practitioner will perform a thorough examination of the penis, scrotum, testicles, I vas deferens, spermatic cords, ejaculatory ducts, urethra, urinary bladder, anus and rectum.
Infestation is the state of being invaded or overrun by pests or parasites. It can also refer to the actual organisms living on or within a host. Terminology
In general, the term "infestation" refers to parasitic diseases caused by animals such as arthropods (i.e. mites, ticks, and lice) and worms, but excluding (except) conditions caused by protozoa, fungi, bacteria, and viruses, which are called infections. External and internal
Infestations can be classified as either external or internal with regards to the parasites location in relation to the host. External or ectoparasitic infestation is a condition in which organisms live primarily on the surface of the host (though porocephaliasis can penetrate viscerally) and includes those involving mites, ticks, head lice and bed bugs.An internal (or endoparasitic) infestation is a condition in which organisms live within the host and includes those involving worms (though swimmers itch stays near the surface). Medically, the term "infestation" is often reserved only for external ectoparasitic infestations while the term infection refers to internal endoparasitic conditions. References
External links
Introduction to Anaerobic Soil Disinfestation as a Fumigant Alternative
New technique predicts risk of plant disease and infestation