Arboviral Diseases in the News
From our previous Product Spotlight, which was our first Rare Disease Journal, we move over to the other end of the spectrum, to some of the most prevalent (and deadly) viruses known. We are speaking of mosquito-borne illnesses, and the following is a list of just of few that are transmitted by their parasites. Included along with a brief overview of the respective diseases, are our related products and some pertinent literature, appearing in both academic and general media recently.
Colorized electron micrograph showing malaria parasite (right, blue) attaching to a human red blood cell. The inset shows a detail of the attachment point at higher magnification. Credit:National Institute of Allergy and Infectious Diseases (NIAID)
Malaria is probably the most well-known to the general public of the diseases in this group and among tropical diseases generally. Approximately half the world’s population (about 100 countries) is at risk.1 Although the disease is prevalent, and attributed to 445,000 deaths as recently as 2016,2 there have been great strides toward decreasing the numbers of people afflicted, through vigorous government and NGO efforts. From 2010-2016 malaria mortality was reduced by 25%.2 For more interesting effects of mosquitos, and specifically, malaria, there is a book to recommend published last month, on the impact of the insect, entitled, The Mosquito A Human History of Our Deadliest Predator. Even more recently, The Lancet commissioned a first-of-its-kind article (open access) which had 41 authors from across a broad range of specialties, with the promising title, Malaria Eradication Within a Generation: Ambitious, Achievable, and Necessary.
Malaria Pv. MSP1
Merozoite surface antigen is a protein located on the outside of the merozoite, playing an imperative role in immune reaction. About 45% cases of malaria are infected by Plasmodium vivax (Pv). Pv. MSP1 has to be used with Plasmodium falciparum (Pf) together for ELISA and rapid diagnostic testing. Plasmodium falciparum and vivax infection covers about 95% of Plasmodium -caused infection.
Malaria Pf. MSP1
About 55% cases of malaria are infected by Plasmodium falciparum (Pf). Pf MSP1 has to be used with Plasmodium vivax (Pv) together for ELISA and rapid diagnostic testing.
Haptoglobin is a glycoprotein which is synthesized in the liver and circulates in the blood. Haptoglobin is produced typically by hepatocytes but also by other tissues: e.g. skin, lung, and kidney. It is a positive acute phase protein that binds free hemoglobin and removes it from the circulation to prevent kidney injury, and iron loss following hemolysis. The haptoglobin-hemoglobin complex is subsequently removed by the reticuloendothelial system (generally the spleen). As the reticuloendothelial system removes the haptoglobin-hemoglobin complex from the body, haptoglobin levels are reduced in hemolytic anaemias. In the course of binding hemoglobin, haptoglobin sequesters the iron inside hemoglobin, preventing iron-utilizing bacteria from benefitting from hemolysis.
Haptoglobin consists of two a- and two b-chains, connected by disulfide bonds. Three major haptoglobin phenotypes are known to exist (Hp 1-1, Hp 2-1, and Hp 2-2). Hp 1-1 is biologically the most effective in binding free hemoglobin and suppressing inflammatory responses associated with free hemoglobin. Hp 2-2 is biologically the least active, and Hp 2-1 is moderately active. Haptoglobin’s molecular mass ranges from 8-200 kDa.
Reduced levels can be seen in haemolysis and impaired liver function. High levels are a marker for acute or chronic inflammation. Ahaptoglobinemia or hypohaptoglobinemia are caused by mutations in the haptoglobin gene and/or its regulatory regions. Haptoglobin is also linked to diabetic nephropathy, the incidence of coronary artery disease in type 1 diabetes, Crohn's disease, inflammatory disease behavior, primary sclerosing cholangitis, susceptibility to idiopathic Parkinson's disease, and a reduced incidence of Plasmodium falciparum malaria.
As the leading cause of domestically acquired arboviral disease in the continental United States,3 a cursory look at search results for the West Nile virus just lists many pages of new occurrences of outbreaks in new regions. According to the CDC, that is the case: incidences were 25% more common than usual in 2018, and transmission patterns appeared to shift to new regions.4
West Nile virus (WNV) is a virus of the family Flaviviridae part of the Japanese encephalitis (JE) antigenic complex of viruses. Image reconstructions and cryoelectron microscopy reveal a 45-50 nm virion covered with a relatively smooth protein surface. This structure is similar to virus; both belong to the genus flavivirus within the family Flaviviridae. WNV is a positive-sense, single strand of RNA, it is between 11,000 and 12,000 nucleotides long which encode seven non-structural proteins and three structural proteins. The RNA strand is held within a nucleocapsid formed from 12 kDa protein blocks; the capsid is contained within a host-derived membrane altered by two viral glycoproteins.
With headlines last month such as, “Philippines Declares a National Dengue Epidemic,” this resurgent disease has killed at least 622 this year in just that country alone. Promisingly, there has also been a vaccine approved by the US Food and Drug Administration (FDA) in May, the first of its kind. Unfortunately, the WHO recommends it only for persons that have had confirmed, prior dengue virus infections.5 In the US, as of September 4, 2019, provisional data states that this year there have been 38 states and the District of Columbia reporting a total of 408 cases, with nearly all being travel related.6
Finally on an individual, very personal level, here is an interesting case, published in the Sunday New York Times Magazine, from their popular column, “Diagnosis”, on some of various ways the Dengue virus can present.
Peptides International has dozens of Dengue virus related products; here are just a couple:
Dengue Virus Subtype 1 & 3 Fused Envelope 58kDa Recombinant
The E.coli derived recombinant 58kDa protein is a genetically engineered peptide which is derived from Dengue Type-1 and 3 to be expressed as a fused envelope, each part in this fusion contains 170 a.a (positions 46-217), it is used in ELISA assay. This fusion protein is connected to a 6xHis Tag.
Dengue Virus NS1 Subtype 2 Recombinant
Recombinant Dengue Virus NS1 Subtype 2 produced in Insect Cells is a polypeptide chain containing amino acids 777-1131 and having a molecular weight of approximately 50kDa.
Longtime readers may be familiar with PI’s “Zika Virus Updates,” a series we instituted during the height of the outbreak. There have been some more developments to report. Earlier this month, it was published in an open access article from Nature Communications that the risk from the virus is not just confined to pregnant or soon-to-be pregnant mothers and their children.7 Understandably, given past publicity of the risks, personal protective measures were greater among female US travelers at least, as shown in a recent study.8 Yet with the Nature Communications study, complacency among the male adult population may be ill-advised. However, in a report from just over a year ago, researchers tested a novel formulation of three free-form amino acids (FFAAP)—cystine, glycine, and glutamate, as well as a minute amount of selenium—that was previously known to increase biosynthesis (or production) of glutathione, an antioxidant, within cells. The Zika virus was inhibited up to 90% in the study.9 On another promising front, a diagnostic test that was given market approval by the US FDA hopefully will remove fear and confusion from those that were possibly exposed or visited affected areas.10
Here are two of our Zika-related products:
Zika virus (ZIKV) belongs to the family Flaviviridae and the genus Flavivirus, it is transmitted by daytime-active Aedes mosquitoes, such as A. aegypti and A. albopictus. The Zika virus is related to the dengue, yellow fever, Japanese encephalitis, and West Nile viruses. Much like the other flaviviruses, Zika virus is enveloped and icosahedral and has a non-segmented, single-stranded, positive-sense RNA genome. Zika fever is an infection, which often causes no symptoms or only mild ones, like a mild form of dengue fever, and it is treated by rest. As of February 2016, there has been mounting evidence that Zika fever in pregnant women can cause abnormal brain development in their fetuses by mother-to-child transmission, which may result in miscarriage or microcephaly. Furthermore, a connection has been established with neurologic conditions in infected adults, including Guillain–Barre syndrome. Since the 1950s, Zika virus has been detected only within a narrow equatorial belt from Africa to Asia. Between the years 2013 and 2014, Zika virus has spread eastward across the Pacific Ocean to French Polynesia, New Caledonia, the Cook Islands, and Easter Island, and in 2015 to Mexico, Central America, the Caribbean, and South America, where the Zika outbreak has reached pandemic levels.
Zika NS1 Paired Antibody/Mouse Anti Zika NS1 Paired
Zika NS1 conjugation antibody and Zika NS1 capture antibody are used to develop rapid test for Zika NS1 rapid test.