Global & Disaster Medicine

Archive for the ‘Malaria’ Category

Is this the end of malaria???????

NYT

“…..In 2016 the disease, which is caused by a parasite and transmitted by mosquitoes, infected 194 million people in Africa and caused 445,000 deaths.

But biologists now have developed a way of manipulating mosquito genetics that forces whole populations of the insect to self-destruct. The technique has proved so successful in laboratory tests that its authors envisage malaria could be eliminated from large regions of Africa within two decades…..”

Nature

The malaria parasite life cycle involves two hosts. During a blood meal, a malaria-infected female Anopheles mosquito inoculates sporozoites into the human host . Sporozoites infect liver cells and mature into schizonts, which rupture and release merozoites . (Of note, in P. vivax and P. ovale a dormant stage [hypnozoites] can persist in the liver and cause relapses by invading the bloodstream weeks, or even years later.) After this initial replication in the liver (exo-erythrocytic schizogony ), the parasites undergo asexual multiplication in the erythrocytes (erythrocytic schizogony ). Merozoites infect red blood cells . The ring stage trophozoites mature into schizonts, which rupture releasing merozoites . Some parasites differentiate into sexual erythrocytic stages (gametocytes) . Blood stage parasites are responsible for the clinical manifestations of the disease. The gametocytes, male (microgametocytes) and female (macrogametocytes), are ingested by an Anopheles mosquito during a blood meal . The parasites’ multiplication in the mosquito is known as the sporogonic cycle . While in the mosquito’s stomach, the microgametes penetrate the macrogametes generating zygotes . The zygotes in turn become motile and elongated (ookinetes) which invade the midgut wall of the mosquito where they develop into oocysts . The oocysts grow, rupture, and release sporozoites, which make their way to the mosquito’s salivary glands. Inoculation of the sporozoites into a new human host perpetuates the malaria life cycle.


Oxitec, Ltd. (“Oxitec”) is entering into a cooperative agreement with the Bill & Melinda Gates Foundation to develop a new strain of Oxitec’s self-limiting Friendly™ Mosquitoes to combat a mosquito species that spreads malaria

Oxitec Press Release

“…….Oxitec will be using its new 2nd generation Friendly™ Mosquito technology to develop an Anopheles albimanus strain to address one of the most important vectors of malaria in the Americas. All of Oxitec’s Friendly™ Mosquito strains are designed to significantly reduce the population of a targeted mosquito species in the wild without impact on human or environmental health. Upon release into the wild, Oxitec’s 2nd generation male-selecting strains mate with wild females, and only male offspring with a self-limiting gene survive to adulthood. The female offspring from these matings – only female mosquitoes bite – will die before reaching adulthood. The surviving non-biting males subsequently seek out and mate with more wild females and pass along the self-limiting trait for up to ten generations before no longer persisting in the environment. When deployed as part of an integrated vector control program, this strain is anticipated to dramatically reduce wild populations of this malaria-transmitting mosquito species, while still ensuring Oxitec self-limiting mosquitoes do not persist in the environment...…..”

 


New anti-malarial netting: A long-lasting insecticidal net that incorporates a synergist piperonyl butoxide (PBO) and a long-lasting indoor residual spraying formulation of the insecticide pirimiphos-methyl.

NY Times

The Lancet

“……The PBO long-lasting insecticidal net and non-pyrethroid indoor residual spraying interventions showed improved control of malaria transmission compared with standard long-lasting insecticidal nets where pyrethroid resistance is prevalent……”

Health workers demonstrating the use of a LLIN in Kisumu, Kenya

“….The new nets contain pyrethroids, a class of chemicals used in nets for over a decade, along with the newer compound, piperonyl butoxide, which blocks mosquitoes’ ability to break down pyrethroids.….”

Net with Anopheles mosquito

 


Between January 2016 and April 2018, six sporadic malaria hospital transmissions have been identified in the EU, in four Member States: Italy (2 cases), Spain (2 cases), Greece (1 case) and Germany (1 case).

ECDC

“…..According to the scientific literature, the following modes of transmission should be taken into account in the investigation of hospital-acquired malaria:

  • Parenteral introduction of blood that contains parasite-infected erythrocytes from one infectious individual to another patient during healthcare procedures;
  • Blood transfusion, or bone marrow or organ transplant from a malaria-infected patient;
  • Accidental contact of blood containing parasite-infected erythrocytes with an open wound…..”

Map of Malaria endemic areas in the world.


Methylene blue & Malaria

NY Times

“……Methylene blue, a dye used to stain tissues viewed under a microscope, can be taken by tablet or injection, and is sometimes used to treat urethral infections and a hemoglobin disorder.

But the dye also kills the malaria parasites in the gametocyte stage, the point at which mosquitoes pick it up from human blood and pass it on to new victims.

Most malaria drugs do not target gametocytes, meaning that someone may still spread the disease for a week or more after treatment……”


Increase of malaria in the Americas

PAHO

Following a continued decrease in the number of malaria cases from 2005 to 2014 in the Region of the Americas, an increase was observed in 2015, 2016, and most recently in 2017. In 2016, 9 countries of the Region (Colombia, Ecuador, El Salvador, Guyana, Haiti, Honduras, Nicaragua, Panama, and the Bolivarian Republic of Venezuela) reported an increase in malaria cases.

In 2017, five countries reported an increase in malaria cases: Brazil, Ecuador, Mexico, Nicaragua, and Venezuela. In addition, Cuba and Costa Rica reported indigenous cases and Honduras reported malaria cases in an area where cases had not been detected recently. Following are summaries of the malaria situation in several countries of the Region.

In Brazil, the International Health Regulations (IHR) National Focal Point reported that between January and November of 2017, there were 174,522 malaria cases reported in the Amazon region, representing an increase in comparison to the same period of 2016 when 117,832 malaria cases were reported. In 2017, the same states, with the exception of Mato Grosso, presented an increase compared to 2016 (Table 1). The states reporting the most cases were Amazonas, Pará, and Acre. In 2017, 10% (17,411 cases) of the reported malaria cases in the Amazon region, correspond to malaria due to P. falciparum and mixed infections, representing a total higher than that reported for the same period in 2015 (14,084) and in 2016 (12,366).

In Costa Rica, the Ministry of Health reported 12 indigenous cases of malaria in 2017, in the cantons of San Carlos (6 cases), Matina (3 cases), and Sarapiqui (3 cases). This represents an increase compared to 2016 when 4 indigenous cases were notified.1,2 The detection of cases in these localities highlights the risk of re-establishment of transmission in areas where ecological conditions persist.

In Ecuador, between epidemiological week (EW) 1 and EW 52 of 2017, a total of 1,279 malaria cases were reported, of these 72% correspond to P. vivax and 28% to P. falciparum.3 The number of cases reported in 2017 is higher than that reported in 2016 (926).4 The four provinces with the highest number of cases in 2017 were Morona Santiago (489), followed by Orellana (240), Pastaza (223), and Esmeraldas (215).

In Honduras, the IHR National Focal Point reported the first indigenous cases of P. vivax malaria on 30 August 2017 in the village of La Charamusca, municipality of Esquías, department of Comayagua. A total of 34 confirmed cases were reported with date of onset of symptoms between EW 27 and 37 of 2017. During the outbreak investigation, the presence of Anopheles pseudopunctipennis was reported as a vector that could be involved in the transmission. The low number of cases registered in the department of Comayagua in the last five years and the absence of transmission for several years in the affected locality, highlights the importance of maintaining surveillance and response capabilities in areas where transmission has been interrupted.

In Mexico, the Secretariat of Health notified 704 malaria cases between EW 1 to EW 50 of 2017, representing an increase from the 514 cases reported in the same period of 2016.5 The increase was particularly notable in the states of Chiapas, Chihuahua, and Tabasco, and highlighted are cases in territories without recent transmission (San Luis Potosí).

In Nicaragua, between EW 1 and EW 52 of 2017, there were 10,846 malaria cases reported, representing an increase compared to the same period in 2016 when 6,209 cases were reported.6 The majority of the cases have been reported from the North Caribbean Coast Autonomous Region.7

The Venezuela, IHR National Focal Point notified the Pan American Health Organization, Regional Office of the World Health Organization (PAHO/WHO), on 27 November 2017, that between EW 1 and EW 42 of 2017 there were 319,765 malaria cases reported between EW and EW 42 of 2017 (Figure 1); representing an increase in comparison to the accumulated reported cases in 2016 (240,613).8

Of the cases reported in 2017, 77% were due to P. vivax, 17% due to P. falciparum, 6% due to mixed infections, and <1% due to P. malariae.

The number of malaria cases reported in 2017 was higher than the annual average recorded in the past 29 years (1988-2016).9

The three states with the highest number of confirmed cases during 2017 were Bolívar (205,215), followed by Amazonas (52,471) and Sucre (45,622). The majority of municipalities in these three states are characterized as having very high and high risk of malaria transmission according to the annual parasitic incidence (API). The risk of malaria is highest in those of 20 to 39 years and account for nearly half of all the cases (47%), showing the risk related to economic activities. Of the total confirmed cases, 64% (203,956) are male and across all age groups more cases in males were reported than in females


Yemen: The World Health Organization estimated that malaria cases rose in 2016 to 433,000 from 336,000 the year before.

Reuters

Map of Malaria endemic areas in the world.

 

The malaria parasite life cycle involves two hosts. During a blood meal, a malaria-infected female Anopheles mosquito inoculates sporozoites into the human host . Sporozoites infect liver cells and mature into schizonts , which rupture and release merozoites . (Of note, in P. vivax and P. ovale a dormant stage [hypnozoites] can persist in the liver and cause relapses by invading the bloodstream weeks, or even years later.) After this initial replication in the liver (exo-erythrocytic schizogony ), the parasites undergo asexual multiplication in the erythrocytes (erythrocytic schizogony ). Merozoites infect red blood cells . The ring stage trophozoites mature into schizonts, which rupture releasing merozoites . Some parasites differentiate into sexual erythrocytic stages (gametocytes) . Blood stage parasites are responsible for the clinical manifestations of the disease.

The gametocytes, male (microgametocytes) and female (macrogametocytes), are ingested by an Anopheles mosquito during a blood meal . The parasites’ multiplication in the mosquito is known as the sporogonic cycle . While in the mosquito’s stomach, the microgametes penetrate the macrogametes generating zygotes . The zygotes in turn become motile and elongated (ookinetes) which invade the midgut wall of the mosquito where they develop into oocysts . The oocysts grow, rupture, and release sporozoites , which make their way to the mosquito’s salivary glands. Inoculation of the sporozoites into a new human host perpetuates the malaria life cycle.


Treatment of Malaria: Guidelines For Clinicians (United States)

CDC

Malaria can be a severe, potentially fatal disease (especially when caused by Plasmodium falciparum) and treatment should be initiated as soon as possible.

Patients who have severe P. falciparum malaria or who cannot take oral medications should be given the treatment by continuous intravenous infusion.

Most drugs used in treatment are active against the parasite forms in the blood (the form that causes disease) and include:

  • chloroquine
  • atovaquone-proguanil (Malarone®)
  • artemether-lumefantrine (Coartem®)
  • mefloquine (Lariam®)
  • quinine
  • quinidine
  • doxycycline (used in combination with quinine)
  • clindamycin (used in combination with quinine)
  • artesunate (not licensed for use in the United States, but available through the CDC malaria hotline)

In addition, primaquine is active against the dormant parasite liver forms (hypnozoites) and prevents relapses. Primaquine should not be taken by pregnant women or by people who are deficient in G6PD (glucose-6-phosphate dehydrogenase). Patients should not take primaquine until a screening test has excluded G6PD deficiency.

How to treat a patient with malaria depends on:

  • The type (species) of the infecting parasite
  • The area where the infection was acquired and its drug-resistance status
  • The clinical status of the patient
  • Any accompanying illness or condition
  • Pregnancy
  • Drug allergies, or other medications taken by the patient

Report a serious drug side effect

If you have had a serious side effect while taking a drug, you or your health care provider can report that side effect to the federal Food and Drug Administration (FDA). MedWatch is the FDA Safety Information and Adverse Event Reporting Program. You are encouraged to take the reporting form to your health care provider.

Alternatively, health care providers can report to the FDA.

The advantage to having your health care provider file the report is that he/she can provide clinical information based on your medical record that can help the FDA evaluate the report.

However, for a variety of reasons, you may not wish to have the form completed by your provider, or the provider may not wish to complete the form. Your health care provider is not required to report to the FDA. In this case, you may complete the online reporting form at www.fda.gov/medwatch/report/consumer/consumer.htm yourself via the Internet.

Related Links

The CDC malaria diagnosis and treatment guidelines have also been published in an article in JAMA May 23, 2007 and can be accessed for free online: view JAMA article.


Malaria outbreak spreads in drug-short Venezuela

Reuters

“…..The government has not given an overall death toll. But health
activists and doctor groups estimate that around 200 people have died
from malaria over the last year [2016] nationwide, and fear the
illness is starting to afflict populated urban centers…….

The regional arm of the World Health Organization last month [October
2017] announced the arrival of over one million anti-malarial pills,
which doctors deem insufficient. Patients must visit their nearest
health center up to 4 times to complete treatment in what officials
say is an attempt to avoid feeding the black market for drugs……”

 

 


EPA Registers the Wolbachia ZAP Strain in Live Male Asian Tiger Mosquitoes in order to reduce their population thereby reducing the spread numerous diseases of significant human health concern

EPA

 

 For Release:  November 7, 2017

On November 3, 2017, EPA registered a new mosquito biopesticide – ZAP Males® – that can reduce local populations of the type of mosquito (Aedes albopictus, or Asian Tiger Mosquitoes) that can spread numerous diseases of significant human health concern, including the Zika virus.

ZAP Males® are live male mosquitoes that are infected with the ZAP strain, a particular strain of the Wolbachia bacterium. Infected males mate with females, which then produce offspring that do not survive. (Male mosquitoes do not bite people.) With continued releases of the ZAP Males®, local Aedes albopictus populations decrease. Wolbachia are naturally occurring bacteria commonly found in most insect species.

This time-limited registration allows MosquitoMate, Inc. to sell the Wolbachia-infected male mosquitoes for five years in the District of Columbia and the following states: California, Connecticut, Delaware, Illinois, Indiana, Kentucky, Massachusetts, Maine, Maryland, Missouri, New Hampshire, New Jersey, Nevada, New York, Ohio, Pennsylvania, Rhode Island, Tennessee, Vermont, and West Virginia. Before the ZAP Males® can be used in each of those jurisdictions, it must be registered in the state or district.

When the five-year time limit ends, the registration will expire unless the registrant requests further action from EPA.

EPA’s risk assessments, along with the pesticide labeling, EPA’s response to public comments on the Notice of Receipt, and the proposed registration decision, can be found on www.regulations.gov under docket number EPA-HQ-OPP-2016-0205.


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