Introduction
H1N1 is a novel strain of Influenza A virus which is evolved by genetic re-assortment. 3 WHO declared H1N1 as a pandemic on 11th June 2009. 3 H1N1 virus can be transmitted to human beings via either contact with infected pigs or environmental contamination with some influenza virus. 4 In India, on May 16, 2009 first confirmed case of H1N1 was found in Hyderabad. Total number of cases reported in India in 2018 was 15266, out of them 1128 cases died. In Andhra Pradesh out of 402 H1N1 detected cases, 17 cases died.
Symptoms like sore throat, fever, cough, severe headache, muscle pains vomiting, diarrhea, respiratory distress, weakness and fatigue are the usual presenting complaints which usually appear in rapid succession. Children and pregnant woman are at risk. In more severe cases, H1N1 causes pneumonia [can be fatal] particularly in the young and the elderly patients. 5 Patients associated with co-morbid conditions like asthma, neurological disorder, diabetes, retro viral disease, chronic immunosuppression, cardiovascular disorder, chronic renal disorder and structural lung disease are more susceptible for getting H1N1 infection. 6 Either in government or private sector, patients with flu like symptoms should be screened and categorized into A, B or C based on severity and associated comorbidities. In order to prevent and contain outbreaks of Influenza, the following guidelines for screening, testing and isolation are to be followed:
Category- A
Uncomplicated or mild illness
Symptoms: cough/ sore throat, mild fever with or without body aches, headache, vomitings and diarrhea.
RT-PCR testing was not required.
Oseltamivir not required. Treated symptomatically.
The patients should be monitored reassessed at 24 to 48 hours. Home isolation advised. Avoid mixing up with public and high-risk members of family.
Category-B
Uncomplicated but severe symptoms or high risk groups.
B1. Along with Category-A symptoms, if the patient has high grade fever and severe sore throat.
B2. Along with Category-A symptoms, individuals having any of the following high-risk conditions (Age more than 65 years, Infants, Children aged ≤ 5 years, Pregnancy, Chronic lung diseases, Chronic heart, liver kidney or neurological disease, Blood disorders, Diabetes mellitus, immunosuppressive states, obesity, Malignancy).
RT-PCR testing was not required.
Oseltamivir should be given along with symptomatic treatment. Home isolation advised. Avoid mixing with public and high-risk members of family.
Category-C
Complicated form
Along with Category-A and Category-B, if the patient has any one or more of the following symptoms and signs:
Symptoms: Shortness of breath, Altered mental status, Hemoptysis, Poor feeding and Somnolence, Seizures, Decreased urine output, Worsening of initial symptoms beyond 72 hours, Worsening of underlying chronic diseases
Signs: Tachypnea, Hypotension, SpO2<90%, Cyanosis.
RT-PCR testing is required. Start empirical antiviral therapy with Oseltamivir without waiting for result. Immediate hospitalization and treatment initiation required.
The present study was conducted
Materials and Methods
400 cases suspected with influenza like illness (cough, sore throat, fever, respiratory distress) from in and out patient units of department of Pulmonary Medicine, Government General Hospital, Kakinada were categorized in to A (250 patients), B (80 patients) and C (70 patients) according to WHO guidelines. Consent was taken from all patients before included in the study. Patients in category C were subjected to RT-PCR by Department of Microbiology. 70 patients were subjected to RT-PCR. 42 cases in them positive for H1N1. Medical records of those 42 patients who confirmed as H1N1 positive by RT-PCR method, were examined thoroughly in the study during a period from October 2018 to April 2019. These 42 cases are the study group and are subjected to battery of tests including chest X-ray, CT Chest, all routine blood and urine examinations.
Results
Table 1
Distribution of various categories among 400 cases
| Category | Total no. | % | RT-PCR | |
| +ve | -ve | |||
| A | 250 | 62.5% | - | - |
| B | 80 | 20% | - | - |
| C | 70 | 17.5% | 42 | 28 |
Table 2
Sex distribution among RT-PCR positive cases (42)
| Gender | Number | % |
| Male | 22 | 52.38 |
| Female | 20 | 47.61 |
Table 3
Age distribution among RT-PCR positive cases (42)
| Age | Number | % |
| 0-20 | 3 | 7.14 |
| 21-30 | 5 | 11.90 |
| 31-40 | 9 | 21.42 |
| 41-50 | 10 | 23.80 |
| 51-60 | 12 | 28.57 |
| >60 | 3 | 7.14 |
Table 4
Travel history among RT-PCR positive cases (42)
| Travel history | Number | % |
| Yes | 9 | 21.42 |
| No | 33 | 78.57 |
Table 5
Presenting complaints among RT-PCR positive cases (42)
| Symptom | Number | % | |
| Cough | 41 | 98.6 | |
| Fever | 33 | 80.67 | |
| Dyspnea grade according to MMRC | 0-2 | 32 | 76.19 |
| 3&4 | 10 | 23.80 |
Table 6
Association with comorbidities among RT-PCR positive cases (42)
| Comorbidity | Number | % |
| Present | 25 | 59.52 |
| absent | 17 | 40.47 |
Table 7
Chest radiograph findings among RT-PCR positive cases (42)
| Chest radiograph | Number | % |
| Normal | 14 | 33.33 |
| Bilateral basal infiltrates | 22 | 52.38 |
| Atypical presentations (lobar pneumonia, upper lobe predilection, unilateral involvement) | 6 | 14.28 |
Table 8
CT chest findings among RT-PCR positive cases (42)
| CT chest | Number | % |
| Normal | 16 | 38.09 |
| Bilateral ground glass opacities and consolidation | 20 | 47.61 |
| Atypical presentation | 6 | 14.28 |
Discussion
Influenza A H1N1 is a highly contagious pathogen which made headlines in 2009, as the so called swine flu, by causing a worldwide influenza pandemic. 3 In India, Influenza virus has been generally ignored in public health and in healthcare. Etiology-specific diagnosis requires lab tests that are not widely available everywhere. 7 Therefore what we know about epidemiology and clinical features are entirely from research studies only.
In present study 400 cases suspected with influenza like illness were included. 62.5% (250) patients were of category A. Category-A patients treated symptomatically. 20% (80) patients were of category-B and treated with Oseltamivir based on weight and symptomatically. Category-A and -B patients advised home isolation. Most patients were treated on out-patient basis. 70 patients suspected with category-C symptoms and their throat swabs subjected to RT-PCR. Out of 70 patients 42 patents were positive for H1N1. Out of 42 patients, 52.38% were males. Males were predominant in my study. Similar results were observed in Chowdary et al., 8 study with 52.1% males and various other Indian studies. 12, 11, 10, 9 Male preponderance than female for H1N1 infection may be due to outdoor work. While the number of female participants were found to be more in studies done outside India like the one study conducted in Kuala Lumpur, Malaysia by Latiff et al., 13 and a study conducted by Lin et al., 14 in China.
In the present study most of the patients 28.57% belonged to 50-60 years age group. Most of the study group was adult population. 4.76%(2) patients were children less than 5years. Srinivasa et al., 15 reported that common age group that suffered with H1N1infection was 21-30 years (60%) followed by 31-40 (30%). Bellei et al., 16 also confirmed the great burden of 2009 pandemic H1N1 infection among young adults.
Here in present study as the age increases the chances of getting infected with H1N1 increases. 59.52% of the patients infected were associated with various comorbidities (Diabetes, CKD, CLD, HIV, steroid therapy, undergoing chemotherapy, structural lung disease, Anemia). Young adults were less in number in the present study. With increasing age immunity decreases and chances of infection were more. This might be the reason for changing trend from young adults to older age group in the present study.78.57% patients were without any travel history. In my study travel history didn’t have significant association with disease.
In my study dyspnea was predominant symptom at presentation, seen in all cases of varying grades. Grade 1 and 2 MMRC in 76.19% cases and Grade 3 and 4 MMRC in 23.80% which was the basis for requirement of hospitalization followed by cough (98.6%) and fever (80.67%). All patients initially have cough and fever but most of them came to hospital after getting dyspnea. All patients had classical symptoms of influenza illness. Choudhry et al., 8 and Broor et al., 17 reported fever as the most common presenting symptoms in their studies. According to study done by Prakash G in 2013, cough was most common presenting symptom followed by fever in 96.46% cases, sore throat in 80.53% cases and breathlessness in 72.56% cases. 4
Negligence of one’s own health in the initial stages and using inappropriate medication from local medical shops for cough and fever may be the reason for presentation with dyspnea in present study. 52.38% cases show bilateral basal inhomogeneous opacities in chest radiographs. 47.61% cases show bilateral ground glass opacities in CT Chest.
In the present study need for respiratory assistance was minimal i.e., in 9.52% (4 cases) among positive cases.4.76% patients died. In Singh et al., study out of 304 H1N1 cases, 58 expired (mortality rate of 19.08%). 3 Mortality rate was less in present study compared to Singh et al. 3 Timely treatment initiation and respiratory assistance provision by noninvasive ventilation, positive cases are less when compared to Singh et al., may well be the reasons for low mortality in present study.
All patients in category C presented with symptoms and signs of complicated influenza illness. All were treated with antiviral therapy (for adults Oseltamivir 75mg BD, for children 30 mg BD oral suspension), IV fluids, O2 supplementation, maintained hydration, electrolyte balance and nutrition. Antibiotics for secondary infection, ventilatory support, vasopressors for patients in shock. In present study 2 cases are less than 5 years old. 3 cases are health care providers. 1 case was of antenatal mother. Cases were kept in swine flu isolation ward. Most of cases need respiratory assistance in the form of non-invasive ventilation. 3 cases needed invasive ventilation. Out of them 2 cases died. 28 patents with category C symptoms, who are negative for H1N1 RT-PCR were treated with Oseltamivir according to weight. Other differentials for viral pneumonia should be considered while treating them.
Older age groups were at increased complication risk in spite of proper treatment. Severity of infection was high in older age groups with comorbidities which led to hospitalization.
Conclusions
H1N1 infection should be considered in the differential diagnosis for patients presenting with fever and respiratory illness or pneumonia. Early detection of H1N1 infection and prompt initiation of treatment is important for preventing complications and mortality. Steps to control the spread of infection are very essential to limit the transmission of H1N1. Flu can be prevented by avoiding close contact with high risk patients and by hand washing, by covering nose and mouth while coughing or sneezing. Adequate rest and proper hydration allows early recovery. Health care providers should take necessary precautions while handling H1N1 cases by means of isolation of positive cases, using N95 masks vaccination for high risk groups to prevent themselves and others getting infected with H1N1.
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