Plasmodium species

Characteristics
Morphology	Plasmodium is an apicomplexan parasite. The asexual stage in the vertebrate host needs the red blood cell (RBC) to survive. Various forms develop inside the RBC, namely, trophozoites, schizonts and merozoites. P. vivax and P. ovale, leave dormant forms in the liver called hypnozoites. The sexual stages responsible for transmission to other vertebrate host are the male and female gametocytes which are picked up by the female Anopheles mosquito when drawing a blood meal. The oocysts develop in the midgut of the mosquito and ultimately sporozoites are stored in the salivary glands until the next blood meal.
Growth Conditions	There are adapted strains of P. falciparum and P. knowlesi, which can be continuously propagated in vitro by adding human or rhesus RBCs. Other species may be maintained in vitro for a short period of time

Characteristics

Morphology

Plasmodium is an apicomplexan parasite. The asexual stage in the vertebrate host needs the red blood cell (RBC) to survive. Various forms develop inside the RBC, namely, trophozoites, schizonts and merozoites. P. vivax and P. ovale, leave dormant forms in the liver called hypnozoites. The sexual stages responsible for transmission to other vertebrate host are the male and female gametocytes which are picked up by the female Anopheles mosquito when drawing a blood meal. The oocysts develop in the midgut of the mosquito and ultimately sporozoites are stored in the salivary glands until the next blood meal.

Growth
Conditions

There are adapted strains of P. falciparum and P. knowlesi, which can be continuously propagated in vitro by adding human or rhesus RBCs. Other species may be maintained in vitro for a short period of time

Health Hazards
Host Range	There are more than 100 species of Plasmodium, which infect a wide range of vertebrates. Five species are recognized to infect humans: P. falciparum, P. vivax, P. malariae, P. ovale, and. P. knowlesi (known to infect macaques, is now recognized to cause a zoonotic infection in humans)
Modes of Transmission	Plasmodium is a blood‐borne pathogen and it can be transmitted via an infected mosquito bite, transfusion, and needle stick.
Signs and Symptoms	Initial merozoites are released from the liver into the blood stream to target RBCs. Symptoms appear when new merozoites are released every other day (P. knowlesi), every second day (tertian P. falciparum, P. vivax, P. ovale) or every third day (quartan, P. malariae). Signs include fever, chills, body ache, sweats, headache
Infectious Dose	A minimal number of Plasmodium‐infected RBCs is needed to initiate an infection. If the infection is initiated by a mosquito bite, the number of sporozoites to be injected will depend on the species of parasite.
Incubation Period	The liver infection initiated by sporozoites injected during a mosquito bite is asymptomatic and may last up to 30 days, depending on the Plasmodium species.

Medical Precautions/Treatment
Prophylaxis	Recommendations for drugs to prevent malaria differ by country. No antimalarial drug is 100% protective and must be combined with the use of personal protective measures, (i.e., insect repellent, long sleeves, long pants, sleeping in a mosquito-free setting or using an insecticide-treated bednet).
Vaccines	Vaccine available, often used in regions where Plasmodium species are endemic
Treatment	Antimalarial drugs are available. Treatment of malaria depends on many factors including disease severity, the species of malaria parasite causing the infection, and the part of the world in which the infection was acquired.
Surveillance	Monitor for symptoms. Microscopic diagnosis, antigen detection, and nucleic acid detection using PCR are common methods to determine if someone if infected
GWU Requirements	Report all incidents to the Office of Risk Management as well as the Office of Research Safety (ORS) IMMEDIATELY FOLLOWING THE OCCURRENCE.

Containment
BSL-2/ABSL-2	Risk Group 2 classification is applied to these parasites. BSL-2 and ABSL-2 practices, including containment equipment/facilities and laboratory personal protective equipment (PPE), are recommended for activities involving infective stages of the parasites. The risks for accidental exposures and occupationally-acquired infections in persons working with cultures, tissue homogenates, blood, or other specimens that contain any of the organisms discussed here, including during procedures that might create aerosols or droplets, should be reduced by use of PPE

Containment

BSL-2/ABSL-2

Risk Group 2 classification is applied to these parasites. BSL-2 and ABSL-2 practices, including containment equipment/facilities and laboratory personal protective equipment (PPE), are recommended for activities involving infective stages of the parasites. The risks for accidental exposures and occupationally-acquired infections in persons working with cultures, tissue homogenates, blood, or other specimens that contain any of the organisms discussed here, including during procedures that might create aerosols or droplets, should be reduced by use of PPE

Spill Procedures
Small Spills (<1 liter)	If the spill occurred inside a biological safety cabinet, close the sash and allow the cabinet to operate for 15 minutes before continuing with the spill cleanup. Plasmodium parasites aerosol transmission is unlikely, but caution should be taken during a spill outside of a BSC. Leave the room immediately and allow the aerosols to dissipate for 15 minutes. Notify others working in the lab. Don appropriate PPE. Cover area of the spill with paper towels or any absorbent material and apply an EPA registered disinfectant effective against parasites (bleach and alcohol), working from the perimeter towards the center. Allow 30 minutes of contact time before disposal and cleanup of spill materials.
Large Spills	Alert lab personnel in the laboratory to the spill and keep people out of the area to prevent spread of the contamination. Check if you have been contaminated or if any of your PPE has been breached. If so follow exposure procedures. Remove any contaminated clothing and place it the biohazard waste. Wash your hands and post a sign on the door. Notify your supervisor of the incident and call ORS (4-8258) for assistance. If the situation involves an imminently life-threatening injury or has catastrophic potential, call 911.

Spill Procedures

Small Spills (<1 liter)

If the spill occurred inside a biological safety cabinet, close the sash and allow the cabinet to operate for 15 minutes before continuing with the spill cleanup.

Plasmodium parasites aerosol transmission is unlikely, but caution should be taken during a spill outside of a BSC. Leave the room immediately and allow the aerosols to dissipate for 15 minutes. Notify others working in the lab. Don appropriate PPE. Cover area of the spill with paper towels or any absorbent material and apply an EPA registered disinfectant effective against parasites (bleach and alcohol), working from the perimeter towards the center. Allow 30 minutes of contact time before disposal and cleanup of spill materials.

Large Spills

Alert lab personnel in the laboratory to the spill and keep people out of the area to prevent spread of the contamination. Check if you have been contaminated or if any of your PPE has been breached. If so follow exposure procedures. Remove any contaminated clothing and place it the biohazard waste. Wash your hands and post a sign on the door. Notify your supervisor of the incident and call ORS (4-8258) for assistance. If the situation involves an imminently life-threatening injury or has catastrophic potential, call 911.

Exposure Procedures
Mucus Membrane	Flush eyes, mouth or nose for 15 minutes at eyewash station.
Other Exposure	For an area not protected by skin, wash with soap and water for 15 minutes (open wounds, sores, etc.)
Reporting	Report ALL injuries to the PI immediately and reported to the Office of Risk Management at [email protected] IMMEDIATELY FOLLOWING THE OCCURRENCE. Exposures that involve a bloodborne-pathogen or recombinant DNA also need to be reported to the Office of Research Safety at [email protected]. If the injury requires immediate medical attention, call GWPD at 202-994-6111 or call 911.
Medical Monitoring	Seek immediate medical evaluation, treatment, and post exposure follow-up at the Employee Health Office at GWU Hospital (900 23rd St., NW, Suite G-1090, Phone: 202-715-4275). Students should go to the Students Health Office at Marvin Center. After hours treatment can be received at the GWU hospital emergency room.

Stability
Disinfection	Plasmodium is susceptible to 70% ethanol and freshly made 10% bleach
Inactivation	Plasmodium is susceptible to heat inactivation, 0.2 mM amustaline and 2 mM glutathione (GSH) treatment can inactivate plasmodium in whole blood
Survival Outside Host	Minimal if at all

Personal Protective Equipment (PPE)
Minimum PPE Requirements	At minimum, personnel are required to don gloves, closed toed shoes, lab coat, and appropriate face and eye protection prior to working with Plasmodium. Additional PPE may be required depending on lab specific SOPs.
Additional Precautions	Additional protection may be worn over laboratory clothing when infectious materials are directly handled, such as solid-front gowns with tight fitting wrists, gloves, and respiratory protection.

References
CDC (https://www.cdc.gov/parasites/malaria/index.html) BMBL 6th Edition (https://www.cdc.gov/labs/BMBL.html) WHO (https://www.who.int/news/item/06-10-2021-who-recommends-groundbreaking-…) ABSA (https://my.absa.org/riskgroups) Inactivation of Plasmodium falciparum (https://onlinelibrary.wiley.com/doi/10.1111/trf.15734)

Plasmodium species

Plasmodium species