A suspected nosocomial malaria case, Riyadh city, March 1997

On March 23, 1997 the infection control committee chairman at Riyadh hospital consulted the Field Epidemiology Training Program about a 14 month old girl with a Plasmodium falciparum infection. On March 21, she presented to hospital A with a four day history of fever and rigors. A blood film showed numerous P. falciparum trophozoites. She was admitted, treated with anti-malarials for one week, and improved clinically.

The patient and her family had never left Riyadh since her birth. They lived in Nadheem, a district in east Riyadh. They were originally from northern Saudi Arabia and had no visitors from malarious areas of Saudi Arabia. Malaria surveillance reports for February and March revealed 62 other malaria cases in Riyadh but all were in persons with recent travel to malarious areas and none were from Nadheem.

From 11 to 17 days (March 1 to 6) before onset of malarial fever this girl had been admitted for asthma and a respiratory infection to the pediatric ward of the same hospital. She did not receive a blood transfusion or other blood products and was discharged in good condition. Malaria parasites were not seen on blood films taken during this initial hospitalization for asthma. However, three patients with P. falciparum infections imported from Gizan were hospitalized on the same ward.

The asthmatic girl had only one exposure in common with the malaria patients. A heparin solution from a common container was used on the intravenous lines (IVLs) and heparin locks (HLs) of the asthma patient and two malaria patients. Two malaria patients had IVLs started using single use, one ml, heparin-filled syringes within one hour before asthma patient had her heparin lock flushed with heparin. In addition the asthma patient and one malaria patient had their HLs flushed at the approximately the same time. However, different nurses had attended the malaria patients and asthma patient for manipulations of the IVL and HL.

All heparin solution for maintenance of 1-IL and IVL came in a multidose (50 ml) soft plastic packet with an injection port. Nurses would fill 1 ml syringes as needed from this container. After filling the syringes the needles were removed and the nozzle of the syringe was attached directly to the IVL or I-IL. The nozzles of syringes used to administer heparin would become contaminated with blood more often after starting an IVL (28%) than when converting an IVL to a HL (17%) than when flushing a HL after medication (2.4%).

Three deviations from ideal procedures were observed. First, syringes could not be disposed of in patients' rooms so nurses might carry heparin syringes along with new syringes in the same container between patients until the used syringes could be discarded. Blood from nozzles of used syringes might be accidentally transferred to unused syringes at this time. Second, since nurses frequently covered for each other it was also possible that one nurse accidentally picked up a partially used heparin syringe from another nurse to use on the asthmatic patient Finally, one pediatrician recalled observing one nurse contaminate the multi-use heparin container with blood. After withdrawing heparin from the heparin packet with a new 1 ml syringe the nurse disattached the syringe from the needle leaving the needle in place through the rubber diaphragm of the injection port. After using the syringe to start an IVL the nurse needed more heparin and reattached the used syringe to the original needle. At this time blood was visible entering the heparin packet. The hospital administration responded by providing point of use syringe disposal in all patients' rooms and switching to single use heparin containers.

Riyadh city and the surrounding rural areas have never been known to support vector-borne malaria transmission. Although Anopheles sergenti does occur in central Saudi Arabia, this potential vector has not been found in or near Riyadh city for the past 10 years. Accordingly, the report of one malaria case in a person who had not left Riyadh requires a full investigation. Mosquitoes carried in luggage or by car have previously been proposed as an explanation for malaria in non-malarious areas, but these reports have been purely conjectural with no epidemiologic or entomologic evidence in support. However, two previous reports provide clear evidence of malaria transmission through heparin containers and heparin locks[1,2).

The incubation period for accidental inoculation of small numbers of infected red cells clearly puts this patient in the hospital for asthma treatment when she was exposed. This exposure is substantiated by the finding of three potential source cases of P. falciparum hospitalized on the same ward at the same time as the potential exposure. Finally, the linkage to the heparin lock and heparin container as the only percutaneous exposure in common to both the malaria patients and the asthma patient suggests that infected erythrocytes were transferred via the heparin container and the heparin syringes.

This incident has more widespread implications. First, in comparison to other blood borne infectious agents malaria is relatively difficult to transmit. Erythrocytes must be intact whereas other infectious agents (e.g. hepatitis B virus) may survive more severe treatment. Second, small deviations from ideal management of intravenous devices can be dangerous and should be avoided at all costs. Third, a recent investigation of post vaccination abscesses revealed that the practice of leaving a needle inserted through the injection port of multidose containers is widespread and allows contamination of vaccines and other injectables[3]. Nurses, hospitals and clinics throughout Saudi Arabia must be alert to this and similar practices which can transmit serious infections to their patients.