A recent surge in the number of reported cases of West Nile Fever across the United States have health authorities concerned. The problem has escalated considerably in recent weeks, affecting individuals across a broad range of states, according to statistical data, collected by the Centers for Disease Control and Prevention (CDC), as of July 30.
West Nile Fever is a medical condition, caused by an RNA-based virus, and is transmitted to humans through a vector, typically the Cluex pipens mosquito, endemic to many countries. Although various species of birds are principally affected, humans, horses and other mammals are also potential hosts. Once human beings become infected, it is difficult for the disease to be transmitted on a human-to-mosquito basis, due to the low level virulence; these infected individuals are known as “dead end” hosts. However, human to human transmission, although infrequent, is possible; cases of babies contracting the disease across the placenta and during breastfeeding have been reported, whereas transmission amongst adults is often observed following blood transfusions and organ donations from infected hosts.
So far, the CDC report a total of 53 cases, within 19 American states. It’s understood that the highest number of cases to have been witnessed in South Dakota, with the number of neuroinvasive and non-neuroinvasive cases amassing to 12. An additional 20 blood donors have been confirmed as infected, following routine blood screening protocols. The neuroinvasive disease state represents those individuals who have suffered meningitis, encephalitis, or acute flaccid paralysis (AFP). For clarity, meningitis refers to inflammation of the mininges, a tri-layer, protective structure which envelopes the brain and spinal cord, whereas encephalitis occurs when the brain (in isolation) is found to be inflamed; if these two clinical problems manifest in unison, however, this condition is termed meningoencephalitis. AFP is a medical condition characterized by muscle fatigue or paralysis, typically with concomitant muscle tone reduction.
Often, cases of the disease go undetected, as most infected human beings remain asymptomatic. The infamous outbreak in New York (1999) was one such case, where four fifths of the population demonstrated no outward signs of disease progression. However, symptomatic individuals often complain of flu-like symptoms, such as intense fever, malaise, nausea, headache, backache and muscle pain (myalgia), alongside ocular problems. Neurological disease symptoms, such as those previously stated, are often a sign of more severe disease progression and require immediate medical intervention.
It must also be said, the statistical datasets include incidents of both “confirmed” and “probable” cases of the pathology. It is quite conceivable that these results are either understated, due to asymptomatic cases going unreported, or overstated, due to some “probable” individuals having not been correctly diagnosed.
The CDC website recommends individuals take the necessary precautions to prevent and control the disease. Using insect repellent, wearing long-sleeved garments, socks and long pants, whilst remaining extra vigilant “during peak mosquito biting hours” are all highly advisable safety measures. Going a stage further, health officials also recommend mosquito-proofing the home; installing repair screens onto doors and windows will prevent mosquito access, whilst disposing of standing water from buckets, gutters, birdbaths etc., will limit mosquito reproduction, bringing down their numbers.
Thus far, there have been three confirmed deaths, caused by the mosquito-borne infection, whilst the disease incidence appears to be spreading ever-further. Public health officials now consider at least a dozen states of Massachusetts to be at risk, alongside a swathe of additional cities and towns that have been classified as at moderate risk, including Abington, Boston, Brockton, Brookline, Dartmouth, Easthampton, Fall River, Freetown, New Bedford, Swansea and Westport. Anne Roach, a spokeswoman working for the state’s Department of Public Health claims: “the change in risk level was based on an assessment of mosquito activity in the area.”
These events also occur just after zip codes across the Bronx, Queens and Staten Island were cleansed with insecticide over the summer period. Harlem has recently received its second report of mosquitoes, carrying the West Nile virus, prompting many to call for similar action in this region. However, the Deputy Health Commissioner for the area, Daniel Kass, recently went on record calling for a more measured approach: “The mere desire of spraying isn’t enough for us to do it… We will monitor 10031 (the Central Harlem zip code) closely.”
With the death toll escalating, and the total number of incidents of the disease also on the up, officials will be hoping they don’t witness similar events to last year, where the highest number of West Nile deaths were recorded, since 2003. The latest spate of tragic deaths will, no doubt, do little to alleviate the concerns of health officials.
By: James Fenner