Download illustrations of most common bacteria and viruses that infect human and diseases caused by them, diagrams of Gram positive and negative bacterial cell wall, HIV infection and replication, bacteriophage structure, and more.

Please note: Free downloads are intended to facilitate healthcare education for people in need in low income countries and can be used for educational purposes only. If you can afford it or if you plan to use the images for commercial purposes, please consider buying instead. You can find a larger image collection at higher resolutions for sale at affordable prices on Alila Medical Media website.

To download: right click on full size image – choose “Save image as” and save it into your computer. By downloading from this website you acknowledge that you agree to our Conditions of Use.
To purchase larger sizes of the image: (left) click on full size image.

Mechanism of allergy (drug,hay fever, asthma...)

Anaphylactic reaction mechanism: antigen bridges the gap between two antibody molecules on mast cell or basophil, triggering massive release of histamine and other mediators.

Herpes simplex virus infection, labeled diagram.

Herpes simplex virus (HSV-1) latent (in trigeminal nerve ganglion) and active infection (cold sores), labeled drawing.

Bacteria morphology, medical drawing.

Diagrams of common bacteria infecting human including staphylococcus aureus, streptococcus pyogenes, bacillus cereus, e coli (escherichia coli), klebsiella pneumoniae, bordetella pertussis, corynebacterium diphtheriae, helicobacter pylori, clostridium botulinum and tetani, neisseria gonorrhoeae, spirochete, treponema pallidum, and more.

Antigen presenting cell functions, labeled diagram.

APC cells engulf enemy cell by phagocytosis and present pieces of antigen on their surface for recognition by T helper cells.

Cytotoxic T cells functions, labeled diagram.

Immune system basics, activation and action of cytotoxic t cells.

Function of T helper cells, labeled diagram.

Immune system basics: activation and action of T helper cells.

HIV attachment to target T cell, labeled diagram.

HIV attaches to target T cell through gp120 and CD4 receptor and coreceptor on host cell.

Morphology of various viruses, diagrams.

Illustration of common viruses that infect human : coronavirus, hepes, papillomavirus, rotavirus, smallpox, ebola, and more.

TB bacteria infection, labeled diagram.

Progression of pulmonary tuberculosis, formation of Ghon complex and tubercles.

Hepatitis viruses comparison, labeled diagram.

Structure of hepatitis A, B, C, D and E viruses, medical illustration.

Phage infecting a bacterium, unlabeled diagram.

Phage injecting DNA into a bacterium, unlabeled drawing.

Phage infecting a bacterium, labeled diagram.

Phage injecting DNA into a bacterium, labeled drawing.

HIV entry to T cell, labeled drawing.

HIV attachment and entry to T cell and becomes a provirus. Labeled diagram

Latent and Active infection by HIV, labeled diagram.

Latent HIV provirus in T cell genome, its reactivation with production of new viral particles and lysis of host cell, labeled.

Structure of a bacteriophage, labeled diagram.

Structure of a phage, a virus that infects bacteria.

Gram negative bacterial cell wall, labeled diagram.

Gram negative bacterial cell wall with outer membrane and only few layers of peptidoglycan.

Gram positive bacterial cell wall, labeled diagram.

Structure of Gram positive bacterial cell wall with many layers of peptidoglycan and teichoic acid.

Bacteria structure, labeled drawing.

Structure of a bacterial cell, labeled diagram.