Chicken embryo as an animal model for gonorrhea

Area of Science:

• Microbiology and Infectious Diseases
• Animal Models in Research

Background:

• Neisseria gonorrhoeae infection parameters require standardization for reproducible research.
• The chicken embryo model offers a viable system for studying gonococcal pathogenesis.

Purpose of the Study:

• To define parameters for Neisseria gonorrhoeae infection in chicken embryos.
• To standardize infectious and lethal doses for Neisseria gonorrhoeae in this model.

Main Methods:

• Infection of 7- to 12-day-old White Leghorn chicken embryos using virulent (T1) and avirulent (T3) Neisseria gonorrhoeae strains.
• Inoculation via yolk sac (YS) and chorioallantoic membrane (CAM) routes.
• Determination of mean lethal dose (LD50) and mean infective dose (ID50).

Main Results:

• Yolk sac inoculation established infection with as few as 1-10 gonococci, with 8-10 day embryos being most susceptible.
• Chorioallantoic membrane inoculation required higher doses (10^5-10^6 CFU) for lethality within 42 hours.
• Strain and colony type influenced infectivity, but agar- and broth-grown organisms yielded similar LD50 and ID50 values.

Conclusions:

• Yolk sac route is more efficient for Neisseria gonorrhoeae infection and lethality in chicken embryos.
• Chicken embryo model provides reproducible gross pathology and LD50/ID50 data for specific gonococcal strains and types.
• Strain-specific variations exist, influencing experimental interpretations.