INTRODUCTION
Malaria is an acute infectious disease caused by infection with a parasite, Plasmodium, transmitted by the bite of a mosquito called Anopheles. This is widespread in most equatorial tropical territories, where the humid, warm environment and the presence of water, especially stagnant water, favor its reproduction and growth.
Many different symptoms of malaria occur with increasing gradations and levels. After the bite of the infected mosquito, most individuals, especially those who have always lived in at-risk areas, remain asymptomatic, that is, although infected, they do not manifest any symptoms. Other individuals, however, manifest the disease with a crescendo of symptoms and increasingly strong and severe manifestations. Delay in diagnosis and treatment can cause symptoms to worsen to the point of death. This may be due to “brain” forms, kidney failure, or other internal deficits. Speed in dealing with this disease can be vital. Waiting and letting time pass unnecessarily can be lethal, as is often the case.
MALARIA IN RESIDENTS OF ENDEMIC AREAS AND TRAVELERS
Living in endemic areas, where infected Anopheles coexist with humans, sting to feed on their blood, and inoculate Plasmodium frequently, means fostering a mechanism for eliciting the cellular immune or antibody response, a protective factor against the parasite. Repeated and symptomless infections are typical situations for those living in malarial areas. In contrast, in these areas, infants and young children, who have not yet developed full immunity against malaria, are at serious risk of disease and are the age groups with the greatest deaths.
In travelers coming from areas where the malarial parasite is absent, the bite of an infected mosquito can cause an infection that, without immune coverage, allows Plasmodium to develop and invade with the “erythrocyte cycle the blood cells,” with gradually exponential growth.
The presence or absence of symptoms and their “degree” of manifestation is greatly conditioned by the response of the immune system.
THE VARIETY OF SYMPTOMS
Worsening malaise; a sense of dizziness; increasing headaches; fatigue and muscle aches; these may be the first symptoms that occur after a few days to those who have been bitten by an infected mosquito. After a few days, heaviness and soreness in the nape of the neck and neck may appear; dull, severe pain in the muscles of the legs and arms; initial sensation of moist skin, particularly noticeable in the abdomen and back. Approximately one week after the first Plasmodium infestation a fever may begin, not always, to present first, accompanied by mild chills; increased sweating and fronto-occipital headache; these symptoms in the following hours or days tend to increase, with an asthenia that does not allow arms and legs to move. Lightheadedness increases and fever may begin to disappear and to reappear with an undulating characteristic every three to four days. Over the next few days, if no action is taken, the sufferer may present with a heavy, reddish, sometimes dark urine; a feeling of heaviness and swelling in the upper abdomen, spleen and liver; worsening mental confusion to a semi-comatose state and eventually irreversible coma and death due to blockage of cerebral circulation by encephalic microthrombosis.
Irritative abdominal symptoms such as even watery diarrhea and feeling of nausea and vomiting are common at the onset of the disease.
All of these symptoms can rarely occur simultaneously. It is more common for a few, the less severe, to occur with a widely varying degree of intensity. Fever, considered a pathognomonic symptom, often does not appear or occurs late. The typical symptom and almost always present is the generalized feeling of malaise and headache, in the early stage with that sense of head muffling.
Malaria is called the “great deceiver” precisely because of this variety of such different symptoms and unpredictable gradations.
As mentioned earlier, fever, mild or very high, is considered the typical symptom of malaria, accompanied by chills and sweating. This set of symptoms result from the body’s response to the lysis of blood cells, the release of endotoxins, catabolites and the release of parasites into the circulatory stream with a defensive reaction of the body’s systems. But this set of symptoms, regularly taken as the only clinical evidence of the presence of plasmodium, is to be considered unreliable in diagnosing the disease because it is often not present. That is, the absence of these symptoms does not rule out diagnostic doubt. “Algid malarias,” i.e., those without fever, are very common, especially in individuals who have had malaria, in those who live for long periods in risk areas, and in those who have developed specific immunity.
The life of the different types of Plasmodium within the organism; their presence and long cohabitation in blood cells and in those within the “liver acini,” which are cell formations that constitute the internal structure of the liver; the presence within certain families of lymphatic cells; all these events affecting the presence of the parasite in the human organism is strongly conditioned by the immune response of each individual.
The reproductive cycles of Plasmodium in the liver and blood cells occur with well-timed and well-timed but conditioned by the response and modulation of the immune system, which also regulates the occurrence of symptoms.
Native populations, living in areas densely populated by Anopheles, due to the constant bites of infected mosquitoes and the constant presence of the malarial parasite in the “red and white” blood cells and also in the lymphocyte organs, constantly reinforce their defensive capacity against Plasmodium. This situation, typical of malarial territories, of “attack” (Plasmodium) and defense (immunity), permanent, allows to arrive at a coexistence between the two
organisms (parasite and host).
Individuals then coexist in malarial environments with mosquitoes and parasites in a form of “commensalism” (peaceful living) but which should not be considered long-lasting. It only takes a decrease in defense systems due to other infections, or traveling to areas where Anopheles and Plasmodium are not present, to lose immunity and defense. This is a typical phenomenon of those living in infected areas: (1) suffering from periodic states of fatigue; (2) experiencing generalized malaise; (3) losing muscle strength; (4) losing work capacity; and (5) slowing down body activities.
In this period of climate change, long dry spells condition the presence of Anopheles in the environment for long periods. The arid climate prevents mosquito life. Then sudden floods, a frequent phenomenon after long periods of drought, induce new reproductive waves of insects. All this favors the disappearance and presence of Plasmodium in these countries with multiple, periodic infections that, due to the periodic loss of defenses, produce serious and often fatal malaria in the population, especially children, which is unforeseen and unpredictable.
This is the same phenomenon that happens to people who expatriate for medium to long periods from their countries and lose their resistance to Plasmodium. Back home they are just as likely to get sick, even with severe forms as any traveler from areas free of the Malaria Plasmodium.
“The great deception of malaria,” with the most diverse symptoms in type and gradation thus stems from the relationship between the immune system and the parasite and explains the onset of different symptoms, and the progression of the disease to increasingly aggressive situations.
From the above it is good to reflect on the following:
– Anyone traveling to malarial areas, coming from countries with this disease, is subject to infection. The manifestation of the disease and symptoms depends on his or her immune response;
– The most important defense against malaria is definitely the use of natural (Neem) or chemical (DEET) repellents that ward off the risk of mosquito bites;
– Prophylaxis with suitable and effective drugs helps decrease the incidence of the disease by chemically attacking Plasmodium. But it is important to know that a weak “natural and innate immune response of the individual” increases the chance of manifesting symptoms after Plasmodium inoculation; (The Covid example is emblematic. During the pandemic, the induced reduction of immune defenses caused a sharp increase in malaria symptoms and even deaths in indigenous populations – WHO statistics 2022). This demonstrates the defensive power of the immune system.
– During the stay and also upon return from a trip from malaria-prone areas, the occurrence of discomfort, such as those described above, even nuanced, should kindle doubt that one has been infected with Plasmodium. The event should be considered possible and probable even for short or very short stays in areas with the presence of Anopheles. Even a few hours is enough to receive infected stings;
– Returning from a trip from malarial-risk areas, if there is discomfort, headache, fever, or other symptoms, first think of the malarial risk and rule out the disease, then think of any other disease you may have developed.
– The statement that in the presence of symptoms of suspected malaria, laboratory tests are always positive, including the highly sensitive PCR, is not true.
“If the slide read in the laboratory is negative, malaria is not there.” This statement is not true and is dangerous. Significant immunity present in an individual can make the presence of the parasite negative. A slide reading made by inexperienced or hasty eyes can give a negative answer even though the parasite is present. The clinical diagnosis, derived from an evaluation of symptoms, cannot be erased by a negative test, the answer to which is not always true.
– A symptomatic individual, with symptoms that worsen over time and with typical manifestations, even with presumed negative tests, should be treated with effective medicine.
– “Intervening as early as possible saves and does no harm, waiting can kill.”
