On August 28, CDC issued an additional Health Alert Network (HAN) Update on locally acquired malaria cases in the US. At this writing, there have been 7 cases of P. vivax in Florida and 1 in Texas as well as 1 case of the even more concerning, P. falciparum in Maryland. This has not happened in the US since 2003. Since malaria can be a severe and even fatal disease, CDC routinely recommends clinicians consider a malaria diagnosis in any traveler returning from malaria-endemic areas. Now, they recommend you add malaria to the differential in any person with unexplained fever, especially in those with new anemia or thrombocytopenia – regardless of their travel history. They will continue surveillance in all three states for an additional 8 weeks after identifying any case. Anopheles mosquitoes, the usual cause of malaria transmission, are in many parts of the country.
Keep in mind that the most crucial consideration in malaria management is recognizing that malaria is a possibility. Unfortunately, delays can and do lead to unnecessary deaths. According to CDC, we have about 2000 cases per year primarily from travelers returning from trips to malaria-endemic regions. In any given year more than 70% of these cases are diagnosed in VFR travelers. Until recently infections have been increasing over the years – except during the beginning of the COVID19 pandemic. Surveillance numbers for malaria in US travelers are always delayed by two or more years as data is first gathered and then carefully analyzed. Numbers through 2020 are depicted in the graph below. Travel health professionals can access the most up-to-date malaria data at the MMWR website https://www.cdc.gov/mmwr/volumes/71/ss/ss7108a1.htm .
Source: CDC
Many nurses in our specialty only provide pre travel services, but understanding best practices for referring and diagnosing malaria is important information for every travel health provider. Remember a case of P. falciparum could lead to death in a matter of days; this is not a diagnosis that can wait days for a lab result to come back. Julie Richards, the author of this TravelByte provides post-travel care at Stanford Student Health and offers these recommendations.
If anyone suspects a case of malaria, I suggest that to provide the best care for your patients and mitigate your risk as a clinician, you:
- Have a low threshold for calling the CDC Malaria Hotline – they are available 24/7 and easy to reach: clinicians can call the CDC Malaria Hotline: (770) 488-7788 or (855) 856-4713 (toll free), Mon–Fri, 9 am–5 pm EST; (770) 488-7100 after hours, weekends, and holidays. You need to know the parasite species and parasitemia level. Get their advice and then refer the patient. If you are an advanced practice nurse with specialized training in tropical medicine, you may be treating these patients yourself in certain circumstances (e.g., uncomplicated malaria). Ideally, you want to have a referral plan set up in advance but even in that instance, appropriate specialty care may not be available. Simply referring the patient to the local emergency department is not adequate. Often, staff with the required level of expertise are not accessible. Call them in advance and let them know the urgent nature of the situation, and document that in your notes.
- You can sometimes contact the hospital infectious disease resident on-call (keep in mind Tropical Medicine is a subspecialty, and the person you reach may not have much experience – or any in that arena). Give the resident or emergency department team the name of the CDC clinician and the phone number of the CDC hotline so they can follow up. Document that in your notes.
- Remember – the standard of care is urgent evaluation, obtaining results, and treatment initiation all within a 24-hour period. This mandates thick and thin smears in combination with an RDT (rapid diagnostic test similar to those for self-diagnosis of Covid 19) – and tracking down those results the same day – not the next day! PCR is mostly useful with species ID confirmation after diagnosis- not for diagnosis itself as it often takes too long to get back. You have to track down these results.
- All nurses providing travel health services should be familiar with the latest CDC algorithm for treatment of malaria.
In addition to the locally acquired cases, there’s plenty of malaria news from abroad. The latest WHO World Malaria Report points out these key developments.
Drug resistance is increasing, and treatment protocols are rapidly evolving by region – there’s also an increase in a new resistant subspecies, Anopheles stephensi. It is now the primary vector in India.
- CDC now recommends resistance testing in every case diagnosed in the US. Most of our patients will likely need to be admitted now until everything is nailed down, and appropriate treatment is underway.
- The resistance is cropping up de novo in multiple areas and not in the usual Greater Mekong subregion.
- Rapid tests are less reliable due to deletions in P. falciparum histidine-rich protein 2 and protein 3 – so we tend to get false negatives. More tests are in the pipeline.
- Resistance to pyrethroids – the primary insecticide – is increasing.
- The mosquito vectors have actually undergone behavioral adaptation – in some areas they bite before dusk now when people are not under a bed net.
The latest guidelines are below – last reviewed June 2023 per CDC:
Malaria Diagnosis and Treatment – US Guidelines for Clinicians
If you haven’t already done so, I would also urge you to update your training. Review the latest CDC Clinician Outreach and Communication Activity (COCA) call from July 20, 2023, on malaria. It is excellent and the slides/transcript are available to download. Also check out the CE program Malaria 101 for the Healthcare Provider.
Respectfully submitted,
Julie Richards,
ATHNA Past President
September 2023
ATHNA 