Infection

Microbes make distinctive lesions
Both focal and over vast regions
Boils and arthritis
Endocarditis
False membranes and pleural adhesions.

In typhoid gut changes are found
Great patches of Peyer profound
Have cell infiltration
And then ulceration
From which salmonella abound.

Strep can make throats red and sore
Sequelae may even do more
Causing nephritis
Rheumatic carditis
From immune reactions galore.

Staph do their best in abscesses
With polys make pus that compresses
Most frequent in skin
Where furuncles begin
Drainage results in successes.

Syphilitic lesions widespread
From the skin to aorta and head
With endarteritis
Luetic orchitis
Then paresis tabes to dread.

Gonococci exert their effect
On the genital tract more direct
Urethra and tube
Inflame and occlude
Obstruction most hard to correct.

Viruses grow within cells
Protected as if they're in shells
Smallpox rubella
Warts varicella
Cause epidermis to swell.

Others affect deeper sites
Diseases producing great frights
Yellow fever and rabies
In adults and babies
From canine and mosquito bites.

Parasites often have vectors
Which serve as the agents' directors
Entering in
By piercing the skin
In tropical zones and hot sectors.

Examples are onchocerciasis
Kala azar trypanosomiasis
Transmitted by
A small biting fly
They differ from schistosomiasis.

This you contract from cercaria
A free swimming form in aquaria
Skin penetrated
Then blood circulated
To liver somewhat like malaria.

But there the resemblance ends
Mosquito's the one that offends
Delivering in bites
Sporozoites
That red cells can never call friends.

Parasites may be ingested
Causing intestines congested
Like amebiasis
Worms giardiasis
Meals then are poorly digested.